电子和光子或电子束和激光对半导体作用的差异或区别和联系

The annealing of semiconductors is of critical importance for successful electronic device fabrication. The present review surveys the new field of transient annealing and covers all timescales below those available with the conventional furnace. The work outlined includes the use of techniques which rely upon transient energy deposition in semiconductors from laser, electron beam, ion beam and other radiant sources. The many advances which have been achieved using these transient annealing methods in both fundamental and applied areas of physics are described.

The operating principles, threshold characteristics, and physical factors imposing restrictions on the main operational parameters are reviewed for semiconductor lasers pumped by beams of accelerated electrons. The attention is focused on electrodynamics of the optical field and on the influence of the cavity configuration on the spectrum of the emitted modes. A brief account is given of the history of these lasers. The problems still not solved are discussed and potential ways of improving these lasers are considered.

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A method was developed for producing a waveguide resonator structure in an electron-beam- pumped semiconductor laser. When guided waves were excited in such a resonator, the laser threshold was found to be independent of the electron energy and the angular distribution of the output radiation was more complex than for a homogeneous resonator. The use of a waveguide resonator made it possible to reduce the laser threshold to 0.3 A/cm2 (in the electron energy range 15–20 keV), which was one or two orders of magnitude lower than for a laser with a homogeneous resonator.

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Laser action is described for total internal reflection modes such that the far-field pattern is a circular ring surrounding the crystal in a plane perpendicular to the rectangular cavity faces. A number of recent experiments have shown that this far-field pattern can be observed in GaAs samples as well as in ZnO and CdS. Experiments are reported for single crystals at a temperature of 77°K pumped by a low-voltage electron beam using 100-ns low-duty cycle pulses. Photographs of the far-field pattern show a narrow line extending 360° around the axis of the crystal and having an angular width of 5 to 10°. Photographs of the near-field pattern indicate that the laser light is emitted in quadrants at the four corners of the rectangular cavity, combining at large distances to produce a 360° pattern. Experimental results on a number of CdS crystals of various thicknesses show that the voltage threshold for lasing (at constant current density) for the total internal reflection mode varies approximately as the 0.7 power of the crystal thickness. Losses from total internal reflection are negligible, and for CdS and ZnO platelets absorption losses are also so small that lasing can occur when the penetration depth of the electrons is only 1/40 of the total crystal thickness. Because of these low losses, lasing has been observed in ZnO and CdS at 2.5 keV and a current density of about 5 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for crystal platelets approximatley 2 microns thick. Since the penetration of a 2.5 keV electron is only about 500 Å, this indicates that surface losses in CdS and ZnO with as-grown surfaces are also small. A similar thickness dependence is reported for GaAs doped with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.5 \times 10^{19}</tex> Zn atoms/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , but absorption losses appear to be higher. Thus a 2-micron-thick crystal of GaAs pumped with an electron beam of the same current density as above lases with a voltage threshold of 10 keV. The threshold voltages measured for ZnO, CdS, and GaAs are considerably lower than any previously reported for electron-beam pumped semiconductor lasers.

A theoretical analysis is made of the active carrier distribution and carrier collection efficiency in threelayer and variable-gap structures in electron-beam-pumped semiconductors. It is shown that these structures make it possible to lower the laser stimulated emission threshold by more than an order of magnitude with a carrier collection efficiency of up to 100%.

The influence of the external and internal resonator parameters on the laser emission spectral and spatial characteristics has been investigated. Single longitudinal mode operation of the electron-beam-pumped visible semiconductor laser with an external resonator has been observed. A single-mode peak power of 0.8 W and beam divergence of less than 3° were achieved.

Abstract Ferromagnetic transition and magnetic anisotropy was studied by SQUID magnetometry and ferromagnetic resonance (FMR) methods in polycrystalline Ge 1‐ x Mn x Te ( x = 0.085) semiconductor microstructures embedded in an amorphous, insulating, and paramagnetic (Ge,Mn)Te matrix. The microstructures were produced by pulsed laser and electron beam induced local re‐crystallization of amorphous layers deposited on insulating BaF 2 substrates. The angular dependence of the FMR resonance field observed below the Curie temperature T C = 70 K of the microstructures is quantitatively described by the analysis of Zeeman and demagnetization contributions to magnetic free energy. Good agreement with experimental results obtained in the case of structures produced by pulsed laser re‐crystallization indicates the formation of ferromagnetic (Ge,Mn)Te thin disks of submicron dimensions.

The operation of an electron-beam pumped laser as the screen of a television projection tube is described. The relationship among electron-beam current, energy, and beam diameter is discussed.

A description of a ZnS semiconductor laser pumped by an electron beam and operating in the scanning regime (with the crystal at a temperature T= 80 K emitting 0.3 W at the wavelength of 330 nm) and in the pulsed regime (300 K, 3 kW at 345 nm).

Differentiated electron-beam-induced current (DEBIC) is shown to be well suited for the study of semiconductor heterostructure lasers. The DEBIC signal, unlike the standard EBIC signal, is rich in fine-structure information in the vicinity of the active region. A simple model is introduced to explain the characteristic DEBIC signal. As a result of the anisotropy of the carrier distribution, higher spatial resolution (≲0.2 μm) is achieved with DEBIC than with the standard technique, EBIC (?1 μm). The DEBIC can be used to obtain diffusion lengths of the minority carriers and to evaluate the quality and uniformity of the device fabrication.

A timing method for experiments on the interaction of a near-infrared laser and an ultra-relativistic electron beam via a semiconductor plasma switch is experimentally validated. As an intermediate medium, a thin Si plate is excited by the energetic, intense electron beam to produce a semiconductor plasma, which in turn deflects counter-colliding laser light having 1 μm wavelength. An electron beam of sub-nC charge sufficiently induces the needed electron number density gradient of 1 × 1020 cm−3 per tens of μm length at the interaction point. Demonstration during an inverse Compton scattering experiment by a counter-colliding electron beam of 300 pC and 70 MeV with an Nd: YAG laser at a wavelength of 1 μm is reported.

A high-current electron-beam-semiconductor pulse amplifier was used to modulate an injection laser. Results show the capability of infrared output having faster rise time and shorter duration than can be obtained with commonly used types of pulse drivers.

The Monte Carlo method is used to calculate the spatial distribution of the density of the absorbed energy and the dimensions of the excited region in GaAs and CdS semiconductor lasers excited by beams of electrons of energies from 10 keV to 20 MeV. The results of the calculations are used to derive an approximate analytic expression convenient for the determination of the distribution of the density of the absorbed energy with depth in the material in a wide range of electron energies. A considerable reduction in the maximum value of the density of the absorbed energy of the pump electrons occurs when the electron beam diameter is small. This is one of the reasons for the increase in the lasing threshold (expressed in terms of the pump current density) on reduction in the size of the electron beam used to excite a laser.

Charging insulating films in a scanning electron microscope is shown to be a potentially useful thermographic technique which makes it possible to reveal hot regions in microelectronic devices, with a spatial resolution in the submicrometer range. This technique entails depositing an insulating film on the device to serve as thermographic medium. A focused, low-energy electron beam charges the insulator during the scanning process. Hot regions modify the local charge, which in turn modifies the secondary electron signal and thus generates a thermal contrast. This technique has been applied to investigate mirrors of GaAs/AlGaAs graded index separate confinement single quantum well laser diodes. Thermographic images of these mirrors have been obtained with a spatial resolution of 0.25 μm. Since the thermal images can be observed using the scanning electron microscope’s TV mode, the course of fast thermal phenomena at laser mirrors can be imaged. As an example, the thermal drift prior to the thermal runaway at laser mirrors has been investigated.

Volume 1: Synthesis and Processing. H.G. Jiang, M.L. Lau, V.L. Telkamp, and E.J. Lavernia, Synthesis of Nanostructured Coatings by High Velocity Oxygen Fuel Thermal Spraying. K.E. Gonsalves, S.P. Rangarajan, and J. Wang, Chemical Synthesis of Nanostructured Metals, Metal Alloys, and Semiconductors. J. Costa, Nanoparticles from Low-Pressure and Low-Temperature Plasma. C.D. Johnson, M. Noh, H. Sellinschegg, R. Schneidmiller, and D.C. Johnson, Kinetic Control of Inorganic Solid State Reactions Resulting from Mechanistic Studies Using Elementally Modulated Reactants. E.J. Gonzalez and G.J. Piermarini, Low Temperature Compaction on Nanosize Powders. W.H. Weinberg, C.M. Reaves, B.Z. Nosho, R.I. Pelzel, and S.P. denBaars, Strained-layer Heteroepitaxy to Fabricate Self-assembled Semiconductor Islands. J.J. McClelland, Nanofabrication via Atom Optics. K.C. Kwaitkowski and C.M. Lukehart, Nanocomposites Prepared by Sol-Gel Methods: Synthesis and Characterization. Q. Yitai, Chemical Preparation and Characterization of Nanocrystalline Materials. D.J. Duval and S.H. Risbud, Semiconductors Quantum Dots-Progress in Processing. I.T.H. Chang, Rapid Solidification Processing of Nanocrystalline Metallic Alloys. K.L. Choy, Vapor Processing of Nanostructured Materials. Volume 2: Spectroscopy and Theory. J.M. Cowley and J.C.H. Spence, Nanodiffraction. M.-I. Baraton, FT-IR Surface Spectrometry of Nanosized Particles. P. Milani and C.E. Bottani, Vibrational Spectroscopy of Mesoscopic Systems. R.M. Taylor II and R. Superfine, Advanced Interfaces to Scanning-probe Microscopes. R. Blick, Microwave Spectroscopy on Quantum Dots. E. Meyer and R. Luthi, Tribological Experiments with Friction Force Microscopy. M. J. Yacaman and J.A. Ascencia, Electron Microscopy Techniques Applied to Study of Nanostructured Materials and Ancient Materials. K. Ounadjela and R.L. Stamps, Mesoscopic Magnetism in Metals. D.J. Whitehouse, Tools of Nanotechnology: Nanometrology. V.Gasparian, M. Ortuno, G. Schon, and U. Simon, Tunneling Times in Nanostructures. S.B. Sinnott, Theory of Atomic-Scale Friction. D. Ahn, Theoretical Aspects of Strained-layer Quantum-Well Lasers. L.R. Ram Mohan, I. Vurgaftman, and J.R. Meyer, Wavefunction Engineering: A New Paradigm in Quantum Nanostructure Modeling. Volume 3: Electrical Properties. J. Smolines and G. Ploner, Electron Transport and Confining Potentials in Semiconductor Nanostructures. M.A. Reed, J.W. Sleight, and M.R. Deshpande, Electron Transport Properties of Quantum Dots. U. Simon and G. Schon, Electrical Properties of Chemically Tailored Nanoparticles and Their Applications in Microelectronics. R.P. Andres, S. Datta, D.B. Janes, C.P. Kubiak, and R. Reifenberger, Design, Fabrication, and Electronic Properties of Self-assembled Molecular Nanostructures. T.P. Sidiki and C.M. Sotomayor Torres, Silicon-based Nanostructures. P.V. Kamat, K. Murakoshi, Y. Wada, and S. Yanagida, Semiconductor Nanoparticles. F.M. Peeters and J. DeBoeck, Hybrid Magnetic-Semiconductor Nanostructures. O.I. Micic and A.J. Nozik, Colloidal Quantum Dots of III-V Semiconductors. V.V. Moshchalkov, Y. Bruynseraede, L. Van Look, M.J. Van Bael, Y. Bruynseraede, and A. Tonomura, Quantization and Confinement Phenomena in Nanostructured Superconductors. M. Graetzel, Properties and Applications of Nanocrystalline Electronic Junctions. S. Mitsui, Nanostructured Fabrication Using Electron Beam and Its Applications to Nanometer Devices. Volume 4: Optical Properties. D.D. Notle, M.R. Melloch, Y. Ding, M. Dinu, K.M. Kwolek, and I. Lahiri, Photorefractive Semiconductor Nanostructures. F. Gonella and P. Mazzoldi, Metal Nanocluster Composite Glasses. D. Thomas, Porous Silicon. W. Chen, Fluorescence, Thermoluminescence, and Photostimulated Luminescence of Nanoparticles. V.M. Shalaev, Surface-enhanced Optical Phenomena in Nanostructured Fractal Materials. V.I. Klimov, Linear and Nonlinear Optical Spectroscopy of Semiconductor Nanocrystals. S. Vijayalakshmi and H. Grebel, Nonlinear Optical Properties of Nanostructures. S.S. Li and M.Z. Tidrow, Quantum Well Infrared Photodetectors. W. Tan and R. Kopelman, Nanoscopic Optical Sensors and Probes. Volume 5: Organics, Polymers, and Biological Materials. P.J. Stang and B. Olenyuk, Transition-Metal-Mediated Self-Assembly of Discrete Nanoscopic Species with Well-Defined Shapes and Geometries. M. Gomez-Lopez and J.F. Stoddart, Molecular and Supramolecular Nanomachines. A.C. Benniston and P.R. Mackie, Functional Nanostructures Incorporating Responsive Modules. A. Archut and F. Voegtle, Dendritic Molecules: Historical Developments and Future Applications. P.M. Ajayan, Carbon Nanotubes. J. Sloan and M.L.H. Green, Encapsulation and Crystallization Behavior of Materials Inside Carbon Nanotubes. H. Kasai, H.S. Nalwa, S. Okada, H. Oikawa, and H. Nakanishi, Fabrication and Spectroscopic Characterization of Organic Nanocrystals. G. Liu, Polymeric Nanostructures. B. Wessling, Conducting Polymers as Organic Nanometals. E. Nakache, N. Poulain, F. Candau, A.M. Orecchioni, and J.M. Irache, Biopolymers and Polymers Nanoparticles and Their Biomedical Applications. T. Bayburt, J. Carlson, B. Godfrey, M. Shank-Retzlaff, and S.G. Sligar, Structure, Behavior, and Manipulation of Nanostructure Biological Assemblies. T.M. Cooper, Biomimetic Thin Films.

Spontaneous periodic surface structures, or ripples, are frequently observed after illumination of metals, semiconductors, and dielectrics by intense laser pulses. We develop a theory which predicts the observed spacing, polarization, and growth properties of these ripples. In this model, one or several Fourier components of a random surface disturbance scatter light from the incident beam very nearly along the surface. The interference of this diffracted optical wave with the incident beam then gives rise to optical interference fringes which can reinforce the initial disturbance. Sinusoidal corrugations on either metallic or molten surfaces seem to provide strong positive feedback for ripple growth, whereas sinusoidal gratings in temperature, electron-hole density, or dielectric constant seem much less well correlated with observations.

On the basis of the known experimental properties of $\frac{1}{f}$ noise, some previous models are analyzed. The presence of $\frac{1}{f}$ noise in the simplest systems such as beams of charged particles in vacuum, the existence of $\frac{1}{f}$ noise in currents limited by the surface recombination rate, bulk recombination rate, or by the finite mobility determined by interaction with the phonons in solids, suggests a fundamental fluctuation of the corresponding elementary cross sections. This leads to fluctuations of the kinetic transport coefficients such as mobility $\ensuremath{\mu}$ or recombination speed, observable both in equilibrium and nonequilibrium. In the first case the available Johnson noise power $\mathrm{kT}$, determined by the Nyquist theorem, is free of this type of $\frac{1}{f}$ fluctuation. An elementary calculation is presented which shows that any cross section, or process rate, involving charged particles, exhibits $\frac{1}{f}$ noise as an infrared phenomenon. For single-particle processes, the experimental value of Hooge's constant is obtained as an upper limit, corresponding to very large velocity changes of the current carriers, close to the speed of light. The obtained ${sin}^{2}(\frac{\ensuremath{\theta}}{2})$ dependence on the mean scattering angle predicts much lower $\frac{1}{f}$ noise for (low-angle) impurity scattering, showing a strong ($\ensuremath{\sim}\frac{{\ensuremath{\mu}}^{2}}{{\ensuremath{\mu}}_{\mathrm{latt}}^{2}}$) noise increase with temperature at the transition to lattice scattering. This is in qualitative agreement with measurements on thin films and on heavily doped semiconductors, or on manganin. The theory is based on the infrared quasidivergence present in all cross sections (and in some autocorrelation functions) due to interaction of the current carriers with massless infraquanta: photons, electron-hole pair excitations at metallic Fermi surfaces, generalized spin waves, transverse phonons, hydrodynamic excitations of other quanta, very low-energy excitations of quasidegenerate states observed, e.g., in disordered materials, at surfaces, or at lattice imperfections, etc. The observed $\frac{1}{f}$ noise is the sum of these contributions, and can be used to detect and study new infraquanta.

Intense ultrashort light pulses comprising merely a few wave cycles became routinely available by the turn of the millennium. The technologies underlying their production and measurement as well as relevant theoretical modeling have been reviewed in the pages of Reviews of Modern Physics (Brabec and Krausz, 2000). Since then, measurement and control of the subcycle field evolution of few-cycle light have opened the door to a radically new approach to exploring and controlling processes of the microcosm. The hyperfast-varying electric field of visible light permitted manipulation and tracking of the atomic-scale motion of electrons. Striking implications include controlled generation and measurement of single attosecond pulses of extreme ultraviolet light as well as trains of them, and real-time observation of atomic-scale electron dynamics. The tools and techniques for steering and tracing electronic motion in atoms, molecules, and nanostructures are now becoming available, marking the birth of attosecond physics. In this article these advances are reviewed and some of the expected implications are addressed.

Electronic excitations lie at the origin of most of the commonly measured spectra. However, the first-principles computation of excited states requires a larger effort than ground-state calculations, which can be very efficiently carried out within density-functional theory. On the other hand, two theoretical and computational tools have come to prominence for the description of electronic excitations. One of them, many-body perturbation theory, is based on a set of Green's-function equations, starting with a one-electron propagator and considering the electron-hole Green's function for the response. Key ingredients are the electron's self-energy \ensuremath{\Sigma} and the electron-hole interaction. A good approximation for \ensuremath{\Sigma} is obtained with Hedin's $\mathrm{GW}$ approach, using density-functional theory as a zero-order solution. First-principles $\mathrm{GW}$ calculations for real systems have been successfully carried out since the 1980s. Similarly, the electron-hole interaction is well described by the Bethe-Salpeter equation, via a functional derivative of \ensuremath{\Sigma}. An alternative approach to calculating electronic excitations is the time-dependent density-functional theory (TDDFT), which offers the important practical advantage of a dependence on density rather than on multivariable Green's functions. This approach leads to a screening equation similar to the Bethe-Salpeter one, but with a two-point, rather than a four-point, interaction kernel. At present, the simple adiabatic local-density approximation has given promising results for finite systems, but has significant deficiencies in the description of absorption spectra in solids, leading to wrong excitation energies, the absence of bound excitonic states, and appreciable distortions of the spectral line shapes. The search for improved TDDFT potentials and kernels is hence a subject of increasing interest. It can be addressed within the framework of many-body perturbation theory: in fact, both the Green's functions and the TDDFT approaches profit from mutual insight. This review compares the theoretical and practical aspects of the two approaches and their specific numerical implementations, and presents an overview of accomplishments and work in progress.

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The European Photon Imaging Camera (EPIC) consortium has provided the focal plane instruments for the three X-ray mirror systems on XMM-Newton. Two cameras with a reflecting grating spectrometer in the optical path are equipped with MOS type CCDs as focal plane detectors (Turner [CITE]), the telescope with the full photon flux operates the novel pn-CCD as an imaging X-ray spectrometer. The pn-CCD camera system was developed under the leadership of the Max-Planck-Institut für extraterrestrische Physik (MPE), Garching. The concept of the pn-CCD is described as well as the different operational modes of the camera system. The electrical, mechanical and thermal design of the focal plane and camera is briefly treated. The in-orbit performance is described in terms of energy resolution, quantum efficiency, time resolution, long term stability and charged particle background. Special emphasis is given to the radiation hardening of the devices and the measured and expected degradation due to radiation damage of ionizing particles in the first 9 months of in orbit operation.

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Preface. 1 Light rays. 1.1 Light rays in human experience. 1.2 Ray optics. 1.3 Reflection. 1.4 Refraction. 1.5 Fermat's principle: the optical path length. 1.6 Prisms. 1.7 Light rays in wave guides. 1.8 Lenses and curved mirrors. 1.9 Matrix optics. 1.10 Ray optics and particle optics. Problems for chapter 1. 2 Wave optics. 2.1 Electromagnetic radiation fields. 2.2 Wave types. 2.3 Gaussian beams. 2.4 Polarization. 2.5 Diffraction. Problems for chapter 2. 3 Light propagation in matter. 3.1 Dielectric interfaces. 3.2 Complex refractive index. 3.3 Optical wave guides and fibres. 3.4 Functional types and applications of optical fibres. 3.5 Photonic materials. 3.6 Light pulses in dispersive materials. 3.7 Anisotropic optical materials. 3.8 Optical modulators. Problems for chapter 3. 4 Optical images. 4.1 The human eye. 4.2 Magnifying glass and eyepiece. 4.3 Microscopes. 4.4 Telescopes. 4.5 Lenses: designs and aberrations. Problems for chapter 4. 5 Coherence and interferometry. 5.1 Young's double slit. 5.2 Coherence and correlation. 5.3 The double-slit experiment. 5.4 Michelson interferometer: longitudinal coherence. 5.5 Fabry-Perot interferometer. 5.6 Optical cavities. 5.7 Thin optical films. 5.8 Holography. 5.9 Laser speckle (laser granulation). Problems for chapter 5. 6 Light and matter. 6.1 Classical radiation interaction. 6.2 Two-level atoms. 6.3 Stimulated and spontaneous radiation processes. 6.4 Inversion and amplification. Problems for chapter 6. 7 The laser. 7.1 The classic system: the He-Ne laser. 7.2 Mode selection in the He-Ne laser. 7.3 Spectral properties of the He-Ne laser. 7.4 Applications of the He-Ne laser. 7.5 Other gas lasers. 7.6 Molecular gas lasers. 7.7 The workhorses: solid-state lasers. 7.8 Selected solid-state lasers. 7.9 Tunable lasers with vibronic states. 7.10 Tunable ring lasers. Problems for chapter 7. 8 Laser dynamics. 8.1 Basic laser theory. 8.2 Laser rate equations. 8.3 Threshold-less lasers and micro-lasers. 8.4 Laser noise. 8.5 Pulsed lasers. Problems for chapter 8. 9 Semiconductor lasers. 9.1 Semiconductors. 9.2 Optical properties of semiconductors. 9.3 The heterostructure laser. 9.4 Dynamic properties of semiconductor lasers. 9.5 Laser diodes, diode lasers, laser systems. 9.6 High-power laser diodes. Problems for chapter 9. 10 Sensors for light. 10.1 Characteristics of optical detectors. 10.2 Fluctuating opto-electronic quantities. 10.3 Photon noise and detectivity limits. 10.4 Thermal detectors. 10.5 Quantum sensors I: photomultiplier tubes. 10.6 Quantum sensors II: semiconductor sensors. 10.7 Position and image sensors. Problems for chapter 10. 11 Laser spectroscopy. 11.1 Laser-induced fluorescence (LIF). 11.2 Absorption and dispersion. 11.3 The width of spectral lines. 11.4 Doppler-free spectroscopy. 11.5 Transient phenomena. 11.6 Light forces. Problems for chapter 11. 12 Photons - an introduction to quantum optics. 12.1 Does light exhibit quantum character? 12.2 Quantization of the electromagnetic field. 12.3 Spontaneous emission. 12.4 Weak coupling and strong coupling. 12.5 Resonance fluorescence. 12.6 Light fields in quantum optics. 12.7 Two-photon optics. 12.8 Entangled photons. Problems for chapter 12. 13 Nonlinear optics I: optical mixing processes. 13.1 Charged anharmonic oscillators. 13.2 Second-order nonlinear susceptibility. 13.3 Wave propagation in nonlinear media. 13.4 Frequency doubling. 13.5 Sum and difference frequency. 13.6 Optical parametric oscillators. Problems for chapter 13. 14 Nonlinear optics II: four-wave mixing. 14.1 Frequency tripling in gases. 14.2 Nonlinear refraction coefficient (optical Kerr effect). 14.3 Self-phase modulation. Problems for chapter 14. Appendix. A Mathematics for optics. A.1 Spectral analysis of fluctuating measurable quantities. A.2 Poynting theorem. B Supplements in quantum mechanics. B.1 Temporal evolution of a two-state system. B.2 Density-matrix formalism. B.3 Density of states. Bibliography. Index.

Preface. 1 Light rays. 1.1 Light rays in human experience. 1.2 Ray optics. 1.3 Reflection. 1.4 Refraction. 1.5 Fermat's principle: the optical path length. 1.6 Prisms. 1.7 Light rays in wave guides. 1.8 Lenses and curved mirrors. 1.9 Matrix optics. 1.10 Ray optics and particle optics. Problems for chapter 1. 2 Wave optics. 2.1 Electromagnetic radiation fields. 2.2 Wave types. 2.3 Gaussian beams. 2.4 Polarization. 2.5 Diffraction. Problems for chapter 2. 3 Light propagation in matter. 3.1 Dielectric interfaces. 3.2 Complex refractive index. 3.3 Optical wave guides and fibres. 3.4 Functional types and applications of optical fibres. 3.5 Photonic materials. 3.6 Light pulses in dispersive materials. 3.7 Anisotropic optical materials. 3.8 Optical modulators. Problems for chapter 3. 4 Optical images. 4.1 The human eye. 4.2 Magnifying glass and eyepiece. 4.3 Microscopes. 4.4 Telescopes. 4.5 Lenses: designs and aberrations. Problems for chapter 4. 5 Coherence and interferometry. 5.1 Young's double slit. 5.2 Coherence and correlation. 5.3 The double-slit experiment. 5.4 Michelson interferometer: longitudinal coherence. 5.5 Fabry-Perot interferometer. 5.6 Optical cavities. 5.7 Thin optical films. 5.8 Holography. 5.9 Laser speckle (laser granulation). Problems for chapter 5. 6 Light and matter. 6.1 Classical radiation interaction. 6.2 Two-level atoms. 6.3 Stimulated and spontaneous radiation processes. 6.4 Inversion and amplification. Problems for chapter 6. 7 The laser. 7.1 The classic system: the He-Ne laser. 7.2 Mode selection in the He-Ne laser. 7.3 Spectral properties of the He-Ne laser. 7.4 Applications of the He-Ne laser. 7.5 Other gas lasers. 7.6 Molecular gas lasers. 7.7 The workhorses: solid-state lasers. 7.8 Selected solid-state lasers. 7.9 Tunable lasers with vibronic states. 7.10 Tunable ring lasers. Problems for chapter 7. 8 Laser dynamics. 8.1 Basic laser theory. 8.2 Laser rate equations. 8.3 Threshold-less lasers and micro-lasers. 8.4 Laser noise. 8.5 Pulsed lasers. Problems for chapter 8. 9 Semiconductor lasers. 9.1 Semiconductors. 9.2 Optical properties of semiconductors. 9.3 The heterostructure laser. 9.4 Dynamic properties of semiconductor lasers. 9.5 Laser diodes, diode lasers, laser systems. 9.6 High-power laser diodes. Problems for chapter 9. 10 Sensors for light. 10.1 Characteristics of optical detectors. 10.2 Fluctuating opto-electronic quantities. 10.3 Photon noise and detectivity limits. 10.4 Thermal detectors. 10.5 Quantum sensors I: photomultiplier tubes. 10.6 Quantum sensors II: semiconductor sensors. 10.7 Position and image sensors. Problems for chapter 10. 11 Laser spectroscopy. 11.1 Laser-induced fluorescence (LIF). 11.2 Absorption and dispersion. 11.3 The width of spectral lines. 11.4 Doppler-free spectroscopy. 11.5 Transient phenomena. 11.6 Light forces. Problems for chapter 11. 12 Photons - an introduction to quantum optics. 12.1 Does light exhibit quantum character? 12.2 Quantization of the electromagnetic field. 12.3 Spontaneous emission. 12.4 Weak coupling and strong coupling. 12.5 Resonance fluorescence. 12.6 Light fields in quantum optics. 12.7 Two-photon optics. 12.8 Entangled photons. Problems for chapter 12. 13 Nonlinear optics I: optical mixing processes. 13.1 Charged anharmonic oscillators. 13.2 Second-order nonlinear susceptibility. 13.3 Wave propagation in nonlinear media. 13.4 Frequency doubling. 13.5 Sum and difference frequency. 13.6 Optical parametric oscillators. Problems for chapter 13. 14 Nonlinear optics II: four-wave mixing. 14.1 Frequency tripling in gases. 14.2 Nonlinear refraction coefficient (optical Kerr effect). 14.3 Self-phase modulation. Problems for chapter 14. Appendix. A Mathematics for optics. A.1 Spectral analysis of fluctuating measurable quantities. A.2 Poynting theorem. B Supplements in quantum mechanics. B.1 Temporal evolution of a two-state system. B.2 Density-matrix formalism. B.3 Density of states. Bibliography. Index.

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In semiconductor photovoltaics, photoconversion efficiency is governed by a simple competition: the incident photon energy is either transferred to the crystal lattice (heat) or transferred to electrons. In conventional materials, energy loss to the lattice is more efficient than energy transferred to electrons, thus limiting the power conversion efficiency. Quantum electronic systems, such as quantum dots, nanowires, and two-dimensional electronic membranes, promise to tip the balance in this competition by simultaneously limiting energy transfer to the lattice and enhancing energy transfer to electrons. By exploring the optical, thermal, and electronic properties of quantum materials, we may perhaps find an ideal optoelectronic material that provides low cost fabrication, facile systems integration, and a means to surpass the standard limit for photoconversion efficiency. Nanoscale carbon materials, such as graphene and carbon nanotubes, provide ideal experimental quantum systems in which to explore optoelectronic behavior for applications in solar energy harvesting. Within essentially the same material, researchers can achieve a broad spectrum of energetic configurations, from a gapless semimetal to a large band-gap semiconducting nanowire. Owing to their nanoscale dimensions, graphene and carbon nanotubes exhibit electronic and optical properties that reflect strong electron-electron interactions. Such strong interactions may lead to exotic low-energy electron transport behavior and high-energy electron scattering processes such as impact excitation and the inverse process of Auger recombination. High-energy processes, which become very important under photoexcitation, may be particularly efficient in nanoscale carbon materials due to the relativistic-like, charged particle band structure and sensitivity to the dielectric environment. In addition, due to the covalently bonded carbon framework that makes up these materials, electron-phonon coupling is very weak. In carbon nanomaterials, strong electron-electron interactions combined with weak electron-phonon interactions results in excellent optical, thermal and electronic properties, the exploration of which promises to reveal fundamentally new physical processes and deliver advanced nanotechnologies. In this Account, we review the results of novel optoelectronic experiments that explore the intrinsic photoresponse of carbon nanomaterials integrated into nanoscale devices. By fabricating gate voltage-controlled photodetectors composed of atomically thin sheets of graphene and individual carbon nanotubes, we are able to fully explore electron transport in these systems under optical illumination. We find that strong electron-electron interactions play a key role in the intrinsic photoresponse of both materials, as evidenced by hot carrier transport in graphene and highly efficient multiple electron-hole pair generation in nanotubes. In both of these quantum systems, photoexcitation leads to high-energy electron-hole pairs that relax energy predominantly into the electronic system, rather than heating the lattice. Due to highly efficient energy transfer from photons into electrons, graphene and carbon nanotubes may be ideal materials for solar energy harvesting devices with efficiencies that could exceed the Shockley-Queisser limit.

The optical properties of monolayer transition metal dichalcogenides (TMDC) feature prominent excitonic natures. Here we report an experimental approach to measuring the exciton binding energy of monolayer WS₂ with linear differential transmission spectroscopy and two-photon photoluminescence excitation spectroscopy (TP-PLE). TP-PLE measurements show the exciton binding energy of 0.71 ± 0.01 eV around K valley in the Brillouin zone.

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Detailed computer simulations are indispensable tools for the development and optimization of modern particle detectors. The interaction of particles with the sensitive medium, giving rise to ionization or excitation of atoms, is stochastic by its nature. The transport of the resulting photons and charge carriers, which eventually generate the observed signal, is also subject to statistical fluctuations. Together with the readout electronics, these processes - which are ultimately governed by the atomic cross-sections for the respective interactions - pose a fundamental limit to the achievable detector performance. Conventional methods for calculating electron drift lines based on macroscopic transport coefficients used to provide an adequate description for traditional gas-based particle detectors such as wire chambers. However, they are not suitable for small-scale devices such as micropattern gas detectors, which have significantly gained importance in recent years. In this thesis, a novel approach, based on semi-classical (``microscopic'') Monte Carlo simulation, is presented. As a first application, the simulation of avalanche fluctuations is discussed. It is shown that the microscopic electron transport method allows, for the first time, a quantitative prediction of gas gain spectra. Further, it is shown that the shape of avalanche size distributions in uniform fields can be understood intuitively in terms of a toy model extracted from the simulation. Stochastic variations in the number of electrons produced along a charged particle track are another determining factor for the resolution and efficiency of a detector. It is shown that the parameters characterizing primary ionization fluctuations, more specifically the so-called W value and the Fano factor, can be calculated accurately using microscopic techniques such that they need no longer be treated as free variables in the simulation. Profiting from recent progress in the determination of Penning transfer probabilities, the influence of excitation transfer on both primary ionization fluctuations and avalanche statistics is examined and a model for the microscopic calculation of Penning effects is proposed. "Garfield'" is a widely used program for the simulation of gas-based particle detectors. In the context of this thesis work, an object-oriented version (Garfield++) of this software package was developed which includes the above-mentioned microscopic methods. The integration of semiconductor detectors in Garfield++, comprising the adaptation of algorithms, modelling of material properties and validation against measurements, constitutes a further topic of the thesis.

We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH(3)NH(3))PbI(3) as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI(2) and deposited onto a submicron-thick mesoscopic TiO(2) film, whose pores were infiltrated with the hole-conductor spiro-MeOTAD. Illumination with standard AM-1.5 sunlight generated large photocurrents (J(SC)) exceeding 17 mA/cm(2), an open circuit photovoltage (V(OC)) of 0.888 V and a fill factor (FF) of 0.62 yielding a power conversion efficiency (PCE) of 9.7%, the highest reported to date for such cells. Femto second laser studies combined with photo-induced absorption measurements showed charge separation to proceed via hole injection from the excited (CH(3)NH(3))PbI(3) NPs into the spiro-MeOTAD followed by electron transfer to the mesoscopic TiO(2) film. The use of a solid hole conductor dramatically improved the device stability compared to (CH(3)NH(3))PbI(3) -sensitized liquid junction cells.

The use of Q-switched ruby laser and multiscanning electron-beam annealing to produce the reaction of thin Ti and Ni films deposited onto silicon single crystals has been studied. Rutherford Backscattering (RBS), 16O(d, p)17O* nuclear reaction, scanning electron microscopy (SEM) observation, and x-ray diffraction were used to characterize the reacted layers. It was found that laser annealing produces a reaction only at the metal-semiconductor interface: the reacted layers are not uniform in composition and more similar to a mixture than to a well-defined phase. On the contrary, the silicide layers produced by multiscanning e beam result from the solid-state reaction of the whole metal film and have a layered structure with well-defined phase composition and sharp interfaces both between the silicide phases and the underlying semiconductor in Ti/Si system. It was observed that the TiSi2 growth mechanism during e irradiation cannot be explained with the parabolic ’’diffusion controlled’’ mechanism operating in the standard furnace annealing. All our observation seems to indicate that the growth mechanism is a ’’nucleation controlled’’ process, in which the growth speed of the disilicide is limited by the speed of ejection of oxygen from a TiSi2 layer. In a Ni/Si system, only the NiSi phase could be obtained as a very uniform layer after the e-beam irradiation; the impossibility of obtaining the Ni2Si phase indicates that, in these conditions, the ’’first-phase nucleation law’’ is no more valid.

Pattern-placement metrology plays a critical role in nanofabrication. Not far in the future, metrology standards approaching 0.2 nm in accuracy will be required to facilitate the production of 25 nm semiconductor devices. They will also be needed to support the manufacturing of high-density wavelength-division-multiplexed integrated optoelectronic devices. We are developing a new approach to metrology in the sub-100 nm domain that is based on using phase-coherent fiducial gratings and grids patterned by interference lithography. This approach is complementary to the traditional mark-detection, or “market plot” pattern-placement metrology. In this article we explore the limitations of laser-interferometer-based mark-detection metrology, and contrast this with ways that fiducial grids could be used to solve a variety of metrology problems. These include measuring process-induced distortions in substrates; measuring patterning distortions in pattern-mastering systems, such as laser and e-beam writers; and measuring field distortions and alignment errors in steppers and scanners. We describe a proposed standard for pattern-placement metrology, which includes both a fiducial grid and market-type marks. Finally, a number of methods through which phase-coherent periodic structures can be patterned are shown, including “traditional” interference lithography, achromatic interference lithography, near-field interference lithography, and scanning-beam interference lithography.

On-surface chemistry for atomically precise sp(2) macromolecules requires top-down lithographic methods on insulating surfaces in order to pattern the long-range complex architectures needed by the semiconductor industry. Here, we fabricate sp(2)-carbon nanometer-thin films on insulators and under ultrahigh vacuum (UHV) conditions from photocoupled brominated precursors. We reveal that covalent coupling is initiated by C-Br bond cleavage through photon energies exceeding 4.4 eV, as monitored by laser desorption ionization (LDI) mass spectrometry (MS) and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) gives insight into the mechanisms of C-Br scission and C-C coupling processes. Further, unreacted material can be sublimed and the coupled sp(2)-carbon precursors can be graphitized by e-beam treatment at 500 °C, demonstrating promising applications in photolithography of graphene nanoarchitectures. Our results present UV-induced reactions on insulators for the formation of all sp(2)-carbon architectures, thereby converging top-down lithography and bottom-up on-surface chemistry into technology.

The interaction of subpicosecond laser pulses with magnetically ordered materials has developed into a fascinating research topic in modern magnetism. From the discovery of subpicosecond demagnetization over a decade ago to the recent demonstration of magnetization reversal by a single $40\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ laser pulse, the manipulation of magnetic order by ultrashort laser pulses has become a fundamentally challenging topic with a potentially high impact for future spintronics, data storage and manipulation, and quantum computation. Understanding the underlying mechanisms implies understanding the interaction of photons with charges, spins, and lattice, and the angular momentum transfer between them. This paper will review the progress in this field of laser manipulation of magnetic order in a systematic way. Starting with a historical introduction, the interaction of light with magnetically ordered matter is discussed. By investigating metals, semiconductors, and dielectrics, the roles of (nearly) free electrons, charge redistributions, and spin-orbit and spin-lattice interactions can partly be separated, and effects due to heating can be distinguished from those that are not. It will be shown that there is a fundamental distinction between processes that involve the actual absorption of photons and those that do not. It turns out that for the latter, the polarization of light plays an essential role in the manipulation of the magnetic moments at the femtosecond time scale. Thus, circularly and linearly polarized pulses are shown to act as strong transient magnetic field pulses originating from the nonabsorptive inverse Faraday and inverse Cotton-Mouton effects, respectively. The recent progress in the understanding of magneto-optical effects on the femtosecond time scale together with the mentioned inverse, optomagnetic effects promises a bright future for this field of ultrafast optical manipulation of magnetic order or femtomagnetism.

Isolation and characterization of mechanically exfoliated black phosphorus flakes with a thickness down to two single-layers is presented. A modification of the mechanical exfoliation method, which provides higher yield of atomically thin flakes than conventional mechanical exfoliation, has been developed. We present general guidelines to determine the number of layers using optical microscopy, Raman spectroscopy and transmission electron microscopy in a fast and reliable way. Moreover, we demonstrate that the exfoliated flakes are highly crystalline and that they are stable even in free-standing form through Raman spectroscopy and transmission electron microscopy measurements. A strong thickness dependence of the band structure is found by density functional theory calculations. The exciton binding energy, within an effective mass approximation, is also calculated for different number of layers. Our computational results for the optical gap are consistent with preliminary photoluminescence results on thin flakes. Finally, we study the environmental stability of black phosphorus flakes finding that the flakes are very hydrophilic and that long term exposure to air moisture etches black phosphorus away. Nonetheless, we demonstrate that the aging of the flakes is slow enough to allow fabrication of field-effect transistors with strong ambipolar behavior. Density functional theory calculations also give us insight into the water-induced changes of the structural and electronic properties of black phosphorus.

The unique characteristics of ultrafast lasers, such as picosecond and femtosecond lasers, have opened up new avenues in materials processing that employ ultrashort pulse widths and extremely high peak intensities. Thus, ultrafast lasers are currently used widely for both fundamental research and practical applications. This review describes the characteristics of ultrafast laser processing and the recent advancements and applications of both surface and volume processing. Surface processing includes micromachining, micro- and nanostructuring, and nanoablation, while volume processing includes two-photon polymerization and three-dimensional (3D) processing within transparent materials. Commercial and industrial applications of ultrafast laser processing are also introduced, and a summary of the technology with future outlooks are also given. Scientists in Asia have reviewed the role of ultrafast lasers in materials processing. Koji Sugioka from RIKEN in Japan and Ya Cheng from the Shanghai Institute of Optics and Fine Mechanics in China describe how femtosecond and picosecond lasers can be used to perform useful tasks in both surface and volume processing. Such lasers can cut, drill and ablate a variety of materials with high precision, including metals, semiconductors, ceramics and glasses. They can also polymerize organic materials that contain a suitable photosensitizer and can three-dimensionally process inside transparent materials such as glass, and are already being used to fabricate medical stents, repair photomasks, drill ink-jet nozzles and pattern solar cells. The researchers also explain the characteristics of such lasers and the interaction of ultrashort, intense pulses of light with matter.

The authors report on the fabrication and characterization of SiO2/TiO2 distributed Bragg reflector (DBR) mirrors operating at the eye safe and optical communication wavelength window, λ = 1.5 μm. Our experimental results demonstrated that SiO2/TiO2 DBR mirrors with reflectivity exceeding 95% at λ = 1.5 μm can be achieved using e-beam evaporation in conjunction with postdeposition thermal annealing process in ambient air. It was found that the postdeposition annealing process transformed the crystal structure of the as-deposited TixOy to TiO2, leading to a significant reduction in optical absorption. Erbium doped III-nitride semiconductors incorporating DBR mirrors at 1.5 μm emission may open up many novel applications, including infrared emitters, optical amplifiers, and high power infrared lasers.

Spin-dependent (SD) phonon Raman scattering of Cd${\mathrm{Cr}}_{2}$${\mathrm{S}}_{4}$ is studied using a circularly polarized beam of a He-Ne (632.8-nm) laser in the Faraday configuration. It is found that magnetic-circular-polarization effects on the SD scattering are due to resonance with the "red-shifting" transitions in this ferromagnetic spinel. Anomalous temperature dependences of the Raman intensity for specific phonon lines $E$ (351 ${\mathrm{cm}}^{\ensuremath{-}1}$) and $F$ (394 ${\mathrm{cm}}^{\ensuremath{-}1}$) are explained by a phenomenological model which takes account of both resonance and magnetic-ordering effects for the scattering process. The mechanism for SD resonance scattering is shown to be closely connected to the absorption process which depends on magnetic ordering. Various models for the red-shifting transitions are discussed in the light of the present resonance Raman-scattering results for this ferromagnetic semiconductor.

High levels of ionization can be created in semiconductor devices by irradiating the devices with short pulses of light. If the light frequency is properly selected, sufficient and relatively uniform energy deposition is obtained which results in ionization rates orders of magnitude above those presently attainable from other sources. It is shown that a pulsed-infrared laser can be used as a relatively simple, inexpensive, and effective means of simulating the effects caused by intense gamma ray sources on semiconductors. Experimental results are presented which show that the transients induced in various types of silicon transistors when exposed to a neodymium laser are essentially identical to those obtained when the transistors are exposed to pulses of 25 MeV electrons from a linear accelerator and 600 kvp flash X-ray machine. Good agreement exists between the peak photocurrents obtained using these three sources over a dose range of 10-1 to 104 rads. Calculations based upon published as well as experimental absorption data for silicon show that energy deposition is very nearly uniform for the wavelength of light obtained from neodymium lasers (1. 06 microns - 1. 17 ev photons). By defocusing the laser light beam, dose rates in excess of 10R12 rads/ sec (silicon) in 40 x 1-99 seconds over an area of 50 cm2 have been obtained from a Q-switched 10 megawatt neodymium laser. This greatly exceeds the maximum dose rate of 1011< rads/ sec silicon) over approximately 1 c2m attainable from linear accelerators.

The complex refractive index N(ω)=n+ik and the complex dielectric constant ε(ω)=ε1+iε2 are presented for diamondlike amorphous carbon (a-C) films in the photon energy range 0.5–7.3 eV. The effective number of valence electrons neff per carbon atom, the static dielectric constant ε0,eff, and the energy loss function Im[−1/ε(ω)] are deduced via the use of sum rules and are used to interpret the optical data. The a-C films were deposited using an unbalanced magnetron gun to sputter a graphite target (effective sputtering area of 20 cm2) in ultrapure argon gas. The magnetron is characterized by a high deposition flux of condensing atoms (1.5×1014–1.2×1016 cm−2 s−1) and a concomitant high ion flux (6×1014–2.5×1016 cm−2 s−1). A series of films were prepared by sputtering at different power levels in the range 5–500 W. Insulating substrates were used which allowed the films to self-bias negatively with respect to the plasma, so that the films were bombarded during their growth by Ar+ ions of energy 16–13 eV at an Ar+/C arrival rate ratio varying from about 4 to 2. A transition in the optical properties, physical properties (density, conductivity, microhardness), and microstructure is observed with the most rapid changes occurring at low sputtering power. The optical data are discussed in terms of interband transitions appropriate to amorphous semiconductors, and by comparison with the optical constants and the band structure of crystalline graphite and diamond. We find that films possess a metastable bonding configuration of a mixture of sp3 (tetrahedral) and sp2 (trigonal) bonds with the average coordination of the carbon atoms varying from 3.76 to 3.44. This fourfold-to-threefold transition in bonding is attributed to ion-induced structural modification of the amorphous carbon matrix. Weak plasma peaks at about 5 eV and the trends in neff and ε0,eff indicate that the π electron is localized leading to a hopping conductivity and a large optical gap, E0=0.40–0.74 eV.

Over the last several decades, innovative light-harvesting devices have evolved to achieve high-efficiency solar energy transfer. Understanding the mechanism of plasmon resonance is very desirable to overcome the conventional efficiency limits of photovoltaics. The influence of localized surface plasmon resonance on hot electron flow at a metal–semiconductor interface was observed with a Schottky diode composed of a thin silver layer on TiO2; subsequent X-ray photoelectron spectroscopy characterized how oxygen in the Ag/TiO2 nanodiode influenced the Schottky barrier height. Photoexcited electrons generate photocurrent when they have enough energy to travel over the Schottky barrier formed at the metal–semiconductor interface. We observed that the photocurrent could be enhanced by optically excited surface plasmons. When the surface plasmons are excited on the corrugated Ag metal surface, they decay into energetic hot electron–hole pairs, contributing to the total photocurrent. The abnormal resonance peaks observed in the incident photons to current conversion efficiency can be attributed to surface plasmon effects. We observed that photocurrent enhancement due to surface plasmons was closely related to the corrugation (or roughness) of the metal surface. While the photocurrent measured on Ag/TiO2 exhibits surface plasmon peaks, the photocurrent on Au/TiO2 does not show any peaks even at the Au surface plasmon energy frequency presumably because of the smoothness of the gold film. We modified the thickness and morphology of a continuous Ag layer using electron beam evaporation deposition and heating under gas conditions and found that morphological changes and the thickness of the Ag film are key factors in controlling the internal photoemission efficiency.

Molecular cocrystals have received much attention for tuning physicochemical properties in pharmaceutics, luminescence, organic electronics, and so on. However, the effective methods for the formation of orderly cocrystal thin films are still rather limited, which have largely restricted their photofunctional and optoelectronic applications. In this work, a fast crystallization-deposition procedure is put forward to obtain acridine (AD)-based cocrystals, which are self-assembled with three typical isophthalic acid derivatives (IPA, IPB, and TMA). The obtained donor-acceptor cocrystal complexes exhibit an adjustable energy level, wide range of photoluminescence color, and rotational angle-dependent polarized emission. The orderly and uniform cocrystal thin films further present tunable one-/two-photon up-conversion and different semiconductor properties. Particularly, AD-TMA cocrystal thin film shows a rare example of a molecule level heterojunction with the alternating arrangement of AD electronic acceptor layers and TMA electronic donor layers, and thus, provides a way for efficient mobility and separation of electron-hole pairs. A large on-off photocurrent ratio of more than 10⁴ can be achieved for the AD-TMA thin film, which is higher than state-of-the-art molecular semiconductor systems. Therefore, this work extends the application scopes of orderly cocrystal thin film materials for future luminescent and optoelectronic micro-/nanodevices.

The wide bandgap semiconductors SiC and GaN are already commercialized as power devices that are used in the automotive, wireless, and industrial power markets, but their adoption into space and avionic applications is hindered by their susceptibility to permanent degradation and catastrophic failure from heavy-ion exposure. Efforts to space-qualify these wide bandgap power devices have revealed that they are susceptible to damage from the high-energy, heavy-ion space radiation environment (galactic cosmic rays) that cannot be shielded. In space-simulated conditions, GaN and SiC transistors have shown failure susceptibility at ∼50% of their nominal rated voltage. Similarly, SiC transistors are susceptible to radiation damage-induced degradation or failure under heavy-ion single-event effects testing conditions, reducing their utility in the space galactic cosmic ray environment. In SiC-based Schottky diodes, catastrophic single-event burnout (SEB) and other single-event effects (SEE) have been observed at ∼40% of the rated operating voltage, as well as an unacceptable degradation in leakage current at ∼20% of the rated operating voltage. The ultra-wide bandgap semiconductors Ga 2 O 3 , diamond and BN are also being explored for their higher power and higher operating temperature capabilities in power electronics and for solar-blind UV detectors. Ga 2 O 3 appears to be more resistant to displacement damage than GaN and SiC, as expected from a consideration of their average bond strengths. Diamond, a highly radiation-resistant material, is considered a nearly ideal material for radiation detection, particularly in high-energy physics applications. The response of diamond to radiation exposure depends strongly on the nature of the growth (natural vs chemical vapor deposition), but overall, diamond is radiation hard up to several MGy of photons and electrons, up to 10 15 (neutrons and high energetic protons) cm −2 and &gt;10 15 pions cm −2 . BN is also radiation-hard to high proton and neutron doses, but h-BN undergoes a transition from sp 2 to sp 3 hybridization as a consequence of the neutron induced damage with formation of c-BN. Much more basic research is needed on the response of both the wide and ultra-wide bandgap semiconductors to radiation, especially single event effects.

SECTION I: PRINCIPLES OF INDUSTRIAL LASERS. Chapter 1: Laser Generation. 1.1 Basic Atomic Structure. 1.2 Atomic Transitions. 1.3 Lifetime. 1.4 Optical Absorption. 1.5 Population Inversion. 1.6 Threshold Gain. 1.7 Two-Photon Absorption. 1.8 Summary. Problems. Chapter 2: Optical Resonators. 2.1 Standing Waves in a Rectangular Cavity. 2.2 Planar Resonators. 2.3 Confocal Resonators. 2.4 Generalized Spherical Resonators. 2.5 Concentric Resonators. 2.6 Stability of Optical Resonators. 2.7 Summary. Problems. Chapter 3: Laser Pumping. 3.1 Optical Pumping. 3.2 Electrical Pumping. 3.3 Summary. Problems. Chapter 4: Rate Equations. 4.1 Two-Level System. 4.2 Three-Level System. 4.3 Four-Level System. 4.4 Summary. Problems. Chapter 5: Broadening Mechanisms. 5.1 Line-Shape Function. 5.2 Line-Broadening Mechanisms. 5.3 Comparison of Individual Mechanisms. 5.4 Summary. Problems. Chapter 6: Beam Modification. 6.1 Quality Factor. 6.2 Q-Switching. 6.3 Q-Switching Theory. 6.4 Mode-Locking. 6.5 Laser Spiking. 6.6 Lamb Dip. 6.7 Summary. Problems. Chapter 7: Beam Characteristics. 7.1 Beam Divergence. 7.2 Monochromaticity. 7.3 Beam Coherence. 7.4 Intensity and Brightness. 7.5 Frequency Stabilization. 7.6 Beam Size. 7.7 Focusing. 7.8 Radiation Pressure. 7.9 Summary. Problems. Chapter 8: Types of Lasers. 8.1 Solid State Lasers. 8.2 Gas Lasers. 8.3 Dye Lasers. 8.4 Semiconductor (Diode) Lasers. 8.5 Free Electron Laser. 8.6 New Developments in Industrial Laser Technology. 8.7 Summary. Problems. Chapter 9: Beam Delivery. 9.1 The Electromagnetic Spectrum. 9.2 Reflection and Refraction. 9.3 Birefringence. 9.4 Brewster Angle. 9.5 Polarization. 9.6 Mirrors and Lenses. 9.7 Beam Expanders. 9.8 Beam Splitters. 9.9 Beam Delivery Systems. 9.10 Summary. Problems. SECTION II: ENGINEERING BACKGROUND. Chapter 10: Heat and Fluid Flow During Laser Processing. 10.1 Energy Balance During Processing. 10.2 Heat Flow in the Workpiece. 10.3 Fluid Flow in Molten Pool. 10.4 Summary. Problems. Chapter 11: The Microstructure. 11.1 Process Microstructure. 11.2 Discontinuities. 11.3 Summary. Problems. Chapter 12: Solidification. 12.1 Solidification Without Flow. 12.2 Solidification With Flow. 12.3 Rapid Solidification. 12.4 Summary. Problems. Chapter 13: Residual Stresses and Distortion. 13.1 Causes of Residual Stresses. 13.2 Basic Stress Analysis. 13.3 Effects of Residual Stresses. 13.4 Measurement of Residual Stresses. 13.5 Relief of Residual Stresses and Distortion. 13.6 Summary. Problems. SECTION III: LASER MATERIALS PROCESSING. Chapter 14: Background on Laser Processing. 14.1 System-Related Parameters. 14.2 Process Efficiency. 14.3 Disturbances that Affect Process Quality. 14.4 General Advantages and Disadvantages of Laser Processing. 14.5 Summary. Problems. Chapter 15: Laser Cutting and Drilling. 15.1 Laser Cutting. 15.2 Laser Drilling. 15.3 New Developments. 15.4 Summary. Problems. Chapter 16: Laser Welding. 16.1 Laser Welding Parameters. 16.2 Welding Efficiency. 16.3 Mechanism of Laser Welding. 16.4 Material Considerations. 16.5 Weldment Discontinuities. 16.6 Advantages and Disadvantages of Laser Welding. 16.7 Special Techniques. 16.8 Specific Applications. 16.9 Summary. Problems. Chapter 17: Laser Surface Modification. 17.1 Laser Surface Heat Treatment. 17.2 Laser Surface Melting. 17.3 Laser Direct Metal Deposition. 17.4 Laser Physical Vapor Deposition. 17.5 Laser Shock Peening. 17.6 Summary. Problems. Chapter 18: Laser Forming. 18.1 Principle of Laser Forming. 18.2 Process Parameters. 18.3 Laser Forming Mechanisms. 18.4 Process Analysis. 18.5 Advantages and Disadvantages. 18.6 Applications. 18.7 Summary. Problems. Chapter 19: Rapid Prototyping. 19.1 Computer-Aided Design. 19.2 Part Building. 19.3 Post-Processing. 19.4 Applications. 19.5 Summary. Problems. Chapter 20: Lasers in Medical and Nano Manufacturing. 20.1 Medical Applications. 20.2 Nanotechnology Applications. 20.3 Summary. Chapter 21: Sensors for Process Monitoring. 21.1 Laser Beam Monitoring. 21.2 Process Monitoring. 21.3 Summary. Problems. Chapter 22: Processing of Sensor Outputs. 22.1 Signal Transformation. 22.2 Data Reduction. 22.3 Pattern Classification. 22.4 Summary. Problems. Chapter 23: Laser Safety. 23.1 Laser Hazards. 23.2 Laser Classification. 23.3 Preventing Laser Accidents. 23.4 Summary.

The usage of semiconductor nanostructures is highly promising for boosting the energy conversion efficiency in photovoltaics technology, but still some of the underlying mechanisms are not well understood at the nanoscale length. Ge quantum dots (QDs) should have a larger absorption and a more efficient quantum confinement effect than Si ones, thus they are good candidate for third-generation solar cells. In this work, Ge QDs embedded in silica matrix have been synthesized through magnetron sputtering deposition and annealing up to 800°C. The thermal evolution of the QD size (2 to 10 nm) has been followed by transmission electron microscopy and X-ray diffraction techniques, evidencing an Ostwald ripening mechanism with a concomitant amorphous-crystalline transition. The optical absorption of Ge nanoclusters has been measured by spectrophotometry analyses, evidencing an optical bandgap of 1.6 eV, unexpectedly independent of the QDs size or of the solid phase (amorphous or crystalline). A simple modeling, based on the Tauc law, shows that the photon absorption has a much larger extent in smaller Ge QDs, being related to the surface extent rather than to the volume. These data are presented and discussed also considering the outcomes for application of Ge nanostructures in photovoltaics.PACS: 81.07.Ta; 78.67.Hc; 68.65.-k.

Nitrogen incorporation in HfO2∕SiO2 films utilized as high-k gate dielectric layers in advanced metal-oxide-semiconductor field effect transistors has been investigated. Thin HfO2 blanket films deposited by atomic layer deposition on either SiO2 or NH3 treated Si (100) substrates have been subjected to NH3 and N2 anneal processing. Several high resolution techniques including electron microscopy with electron energy loss spectra, grazing incidence x-ray diffraction, and synchrotron x-ray photoelectron spectroscopy have been utilized to elucidate chemical composition and crystalline structure differences between samples annealed in NH3 and N2 ambients as a function of temperature. Depth profiling of core level binding energy spectra has been obtained by using variable kinetic energy x-ray photoelectron spectroscopy with tunable photon energy. An “interface effect” characterized by a shift of the Si4+ feature to lower binding energy at the HfO2∕SiO2 interface has been detected in the Si 1s spectra; however, no corresponding chemical state change has been observed in the Hf 4f spectra acquired over a broad range of electron take-off angles and surface sensitivities. The Si 2p spectra indicate Si–N bond formation beneath the HfO2 layer in the samples exposed to NH3 anneal. The NH3 anneal ambient is shown to produce a metastable Hf–N bond component corresponding to temperature driven dissociation kinetics. These findings are consistent with elemental profiles across the HfO2∕Si(100) interface determined by electron energy loss spectroscopy measurements. X-ray diffraction measurements on similarly treated films identify the structural changes resulting from N incorporation into the HfO2 films.

The joining of semiconductor nanowires (NWs) is fundamental for the construction and assembly of high performance nanoelectronic devices, but the development of reliable methods of nanojoining and nanowelding of these components has been elusive to date. In this work, we report a methodology for laser welding of wide bandgap NWs based on two-photon absorption. Two photon excitation during femtosecond laser irradiation leads to the generation of excitons forming an electron-hole plasma. As an application of this technique, we show that two-photon excitation is effective in the nanowelding of two ZnO NWs. A nanoweld, resulting in the formation of an interconnected structure, occurs when the energy in the solid state plasma is deposited in the contact area between the two ZnO NWs. During excitation with ultrashort laser pulses, rapid melting and solidification result in the generation and freezing out of oxygen vacancies in the irradiated area and the region near the contact between the two components. This enhances exciton trapping and energy deposition at the contact, facilitating the formation of a bond between the two NWs. It is also found that the absorption of visible light is significantly increased in ZnO NW structures assembled via two-photon femtosecond laser processing. In addition, the junction between two ZnO NWs created in this way exhibits a photoresponse that is not present prior to nanojoining. These results indicate that two-photon excitation is a promising technique for the selective deposition of thermal energy in semiconductor NWs in the absence of plasmonic interactions.

Preface. 1 Introduction. 1.1 Nanometers, Micrometers, Millimeters. 1.2 Moores Law. 1.3 Esakis Quantum Tunneling Diode. 1.4 Quantum Dots of Many Colors. 1.5 GMR 40Gb Hard Drive Read Heads. 1.6 Accelerometers in your Car. 1.7 Nanopore Filters. 1.8 Nanoscale Elements in Traditional Technologies. 2 Systematics of Making Things Smaller, Pre--quantum. 2.1 Mechanical Frequencies Increase in Small Systems. 2.2 Scaling Relations Illustrated by a Simple Harmonic Oscillator. 2.3 Scaling Relations Illustrated by Simple Circuit Elements. 2.4 Thermal Time Constants and Temperature Differences Decrease. 2.5 Viscous Forces Become Dominant for Small Particles in Fluid Media. 2.6 Frictional Forces can Disappear in Symmetric Molecular Scale Systems. 3 What are Limits to Smallness? 3.1 Particle (Quantum) Nature of Matter: Photons, Electrons, Atoms, Molecules. 3.2 Biological Examples of Nanomotors and Nanodevices. 3.2.1 Linear Spring Motors. 3.2.2 Linear Engines on Tracks. 3.2.3 Rotary Motors. 3.2.4 Ion Channels, the Nanotransistors of Biology. 3.3 How Small can you Make it? 3.3.1 What are the Methods for Making Small Objects? 3.3.2 How Can you See What you Want to Make? 3.3.3 How Can you Connect it to the Outside World? 3.3.4 If you Cant See it or Connect to it, Can you Make it Self--assemble and Work on its Own? 3.3.5 Approaches to Assembly of Small Three--dimensional Objects. 4 Quantum Nature of the Nanoworld. 4.1 Bohrs Model of the Nuclear Atom. 4.1.1 Quantization of Angular Momentum. 4.1.2 Extensions of Bohrs Model. 4.2 Particle--wave Nature of Light and Matter, DeBroglie Formulas k= h/p, E = hv. 4.3 Wavefunction W for Electron, Probability Density WW, Traveling and Standing Waves. 4.4 Maxwells Equations E and B as Wavefunctions for Photons, Optical Fiber Modes. 4.5 The Heisenberg Uncertainty Principle. 4.6 Schrodinger Equation, Quantum States and Energies, Barrier Tunneling. 4.6.1 Schrodinger Equations in one Dimension. 4.6.2 The Trapped Particle in one Dimension. 4.6.3 Reflection and Tunneling at a Potential Step. 4.6.4 Penetration of a Barrier. 4.6.5 Trapped Particles in Two and Three Dimensions: Quantum Dot. 4.6.6 2D Bands and Quantum Wires. 4.6.7 The Simple Harmonic Oscillator. 4.6.8 Schrodinger Equation in Spherical Polar Coordinates. 4.7 The Hydrogen Atom, One--electron Atoms, Excitons. 4.8 Fermions, Bosons and Occupation Rules. 5 Quantum Consequences for the Macroworld. 5.1 Chemical Table of the Elements. 5.2 Nano--symmetry, Di--atoms, and Ferromagnets. 5.2.1 Indistinguishable Particles, and their Exchange. 5.2.2 The Hydrogen Molecule, Di--hydrogen: The Covalent Bond. 5.3 More Purely Nanophysical Forces: van der Waals, Casimir, and Hydrogen Bonding. 5.3.1 The Polar and van der Waals Fluctuation Forces. 5.3.2 The Casimir Force. 5.3.3 The Hydrogen Bond. 5.4 Metals as Boxes of Free Electrons: Fermi Level, DOS, Dimensionality. 5.5 Periodic Structures (e.g. Si, GaAs, InSb, Cu): Kronig--Penney Model for Electron Bands and Gaps. 5.6 Electron Bands and Conduction in Semiconductors and Insulators 97 5.7 Hydrogenic Donors and Acceptors 102 5.8 More about Ferromagnetism, the Nanophysical Basis of Disk Memory 103 5.9 Surfaces are different, Schottky barrier thickness W = [2eeoVB/eND]1/2. 6 Self--assembled Nanostructures in Nature and Industry. 6.1 Carbon Atom 12 6 C 1s 2 2p 4 (0.07 nm). 6.2 Methane CH4, Ethane C 2 H 6 , and Octane C 8 H 18 . 6.3 Ethylene C 2 H 4 , Benzene C 6 H 6 , and Acetylene C 2 H 2 . 6.4 C 60 Buckyball ~0.5nm. 6.5 C infinity Nanotube ~0.5nm. 6.6 InAs Quantum Dot ~5nm. 6.7 AgBr Nanocrystal 0.1--2 mm. 6.8 Fe 3 O 4 Magnetite and Fe 3 S 4 Greigite Nanoparticles in Magnetotactic Bacteria. 6.9 Self--assembled Monolayers on Au and Other Smooth Surfaces. 7 Physics--based Experimental Approaches to Nanofabrication and Nanotechnology. 7.1 Silicon Technology: the INTEL--IBM Approach to Nanotechnology. 7.1.1 Patterning, Masks, and Photolithography. 7.1.2 Etching Silicon. 7.1.3 Defining Highly Conducting Electrode Regions. 7.1.4 Methods of Deposition of Metal and Insulating Films. 7.2 Lateral Resolution (Linewidths) Limited by Wavelength of Light, now 180nm. 7.2.1 Optical and x--ray Lithography. 7.2.2 Electron--beam Lithography. 7.3 Sacrificial Layers, Suspended Bridges, Single--electron Transistors. 7.4 What is the Future of Silicon Computer Technology? 7.5 Heat Dissipation and the RSFQ Technology. 7.6 Scanning Probe (Machine) Methods: One Atom at a Time. 7.7 Scanning Tunneling Microscope (STM) as Prototype Molecular Assembler. 7.7.1 Moving Au Atoms, Making Surface Molecules. 7.7.2 Assembling Organic Molecules with an STM. 7.8 Atomic Force Microscope (AFM) Arrays. 7.8.1 Cantilever Arrays by Photolithography. 7.8.2 Nanofabrication with an AFM. 7.9 Fundamental Questions: Rates, Accuracy and More. 8 Looking into the Future. 8.1 Drexlers Mechanical (Molecular) Axle and Bearing. 8.1.1 Smalleys Refutation of Machine Assembly. 8.1.2 Van der Waals Forces for Frictionless Bearings? 8.2 The Concept of the Molecular Assembler is Flawed. 8.3 Could Molecular Machines Revolutionize Technology or even Selfreplicate to Threaten Terrestrial Life? 8.4 What about Genetic Engineering and Robotics? 8.5 Is there a Posthuman Future as Envisioned by Fukuyama? Exercises. Index.

Introduction. The Advent of Ultrathin, Well-Contained Semiconductor Heterostructures. A Prerequisite. The Mastering of Semiconductor Purity and Interfaces. The Electronic Properties of Thin Semiconductor Heterostructures. Quantum Well Energy Levels. Triangular Quantum Well Energy Levels. Two-Dimensional Density of States. Excitons and Shallow Impurities in Quantum Wells. Tunneling Structures, Coupled Quantum Wells, and Superlattices. Modulation Doping of Heterostructures. n-i-p-i Structures. Optical Properties of Thin Heterostructures. Optical Matrix Element. Selection Rules. Energy Levels, Band Discontinuities, and Layer Fluctuations. Low Temperature Luminescence. Carrier and Exciton Dynamics. Inelastic Light Scattering. Non-Linear and Electro-Optic Effects. Electrical Properties of Thin Heterostructures. Mobility in Parallel Transport. Hot Electron Effects in Parallel Transport. Perpendicular Transport. Quantum Transport. Applications of Quantized Semiconductor Heterostructures. Electronic Devices Based on Parallel Transport. Electronic Devices Based on Perpendicular Transport. Quantum Well Lasers. Towards 1D and 0D Physics and Devices. One- and Zero-Dimensional Systems. 1D and 0D Semiconductor Fabrication Techniques. Electrical Applications of 1D and 0D Structures. 1D and 0D Optical Devices. Selected Bibliography. References. Index.

Preface Instrumentation and Methods Terahertz Time-Domain Spectroscopy with Photoconductive Antennas R. Alan Cheville Nonlinear Optical Techniques for Terahertz Pulse Generation and Detection-Optical Rectification and Electrooptic Sampling Ingrid Wilke and Suranjana Sengupta Time-Resolved Terahertz Spectroscopy and Terahertz Emission Spectroscopy Jason B. Baxter and Charles A. Schmuttenmaer Applications in Physics and Materials Science Time-Resolved Terahertz Studies of Carrier Dynamics in Semiconductors, Superconductors, and Strongly Correlated Electron Materials Robert A. Kaindl and Richard D. Averitt Time-Resolved Terahertz Studies of Conductivity Processes in Novel Electronic Materials Jie Shan and Susan L. Dexheimer Optical Response of Semiconductor Nanostructures in Terahertz Fields Generated by Electrostatic Free-Electron Lasers Sam Carter, John Cerne, and Mark S. Sherwin Applications in Chemistry and Biomedicine Terahertz Spectroscopy of Biomolecules Edwin J. Heilweil and David F. Plusquellic Pharmaceutical and Security Applications of Terahertz Spectroscopy J. Axel Zeitler, Thomas Rades, and Philip F. Taday Index

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The carrier dynamics in photoexcited semiconductors is studied in a quantum kinetic approach based on the density-matrix formalism. Besides the memory effects related to the energy-time uncertainty, we discuss interference effects between different types of interactions describing the fact that a transition due to one interaction occurs between states, which are renormalized by other interactions. We first analyze the relaxation process in a one-band model, which allows us to concentrate on memory effects in the electron-phonon interaction. We then extend the model to a two-band semiconductor interacting with a short laser pulse, which is more realistic due to the explicit treatment of the carrier generation process. Here we discuss, in particular, the role of renormalization effects. It turns out that these effects reduce the broadening due to the non-Markovian dynamics and lead to distribution functions, which are more similar to the semiclassical case; the positions of the peaks, however, exhibit slight time-dependent shifts. On the other hand, phonon quantum beats in the decay of the interband polarization are increased by these renormalization effects.

The performance of semiconductor materials in solar water splitting and other applications is strongly influenced by the structure-related dynamics of charge carriers in these materials. In this study, we assessed the trapping, recombination, and surface reactions of photogenerated and electrically injected charges on specific facets of the promising visible active photocatalyst BiVO4 by using single-particle photoluminescence (PL) spectroscopy. Evaluation of the electric-potential-induced PL properties and the PL response to charge scavengers revealed that the visible PL bands observed during visible laser irradiation originate from radiative recombination between holes trapped at the intraband states above the valence band and mobile (free or shallowly trapped) electrons. Furthermore, the trapped holes are preferentially located on the lateral {110} facets of the BiVO4 crystal, while the electrons are uniformly distributed over the crystal. The methodology described in this study thus provides us with a unique opportunity to explore whether or not the crystal faces affect the charge carrier dynamics in the photocatalysis and the photoelectrocatalysis.

Charge-carrier recombination dynamics after a pulsed laser excitation are investigated by time-resolved microwave conductivity (TRMC) for quantum-sized (Q-) TiO2 and P25, a bulk-phase TiO2. Adsorbed scavengers such as HNO3, HCl, HClO4, isopropyl alcohol, trans-decalin, tetranitromethane, and methyl viologen dichloride result in different charge-carrier recombination dynamics for Q-TiO2 and P25. The differences include a current doubling with isopropyl alcohol for which electron injection into Q-TiO2 is much slower than into P25 and relaxation of the selection rules of an indirect-bandgap semiconductor due to size quantization. However, the faster interfacial charge transfer predicted for Q-TiO2 due to a 0. 2 eV gain in redox overpotentials is not observed. The effect of light intensity is also investigated. Above a critical injection level, fast recombination channels are opened, which may be a major factor resulting in the dependence of the steady-state photolysis quantum yields on l–1/2. The fast recombination channels are opened at lower injection levels for P25 than for Q-TiO2, and a model incorporating the heterogeneity of surface-hole traps is presented.

Bismuth vanadate (BiVO4) is a promising semiconductor material for photoelectrochemical water splitting showing good visible light absorption and a high photochemical stability. To improve the performance of BiVO4, it is of key importance to understand its photophysics upon light absorption. Here we study the carrier dynamics of BiVO4 prepared by the spray pyrolysis method using broadband transient absorption spectroscopy (TAS), in thin films as well as in a photoelectrochemical (PEC) cell under water-splitting conditions. The use of a dual-laser setup consisting of electronically synchronized Ti:sapphire amplifiers enable us to measure the femtosecond to microsecond time scales in a single experiment. On the basis of this data, we propose a model of carrier dynamics that includes relaxation and trapping rates for electrons and holes. Hole trapping occurs in multiple phases, with the majority of the photogenerated holes being trapped with a time constant of 5 ps and a small fraction of this hole trapping taking place within the instrument response of 120 fs. The induced absorption band that represents the trapped holes is modulated by an oscillation of 63 cm–1, which is assigned to the coupling of holes to a phonon mode. We find electrons to undergo a relaxation with a time constant of 40 ps, followed by deeper trapping on the 2.5 ns time scale. On time scales longer than 10 ns, trap-limited recombination that follows a power law is found, spanning time scales up to microseconds. Finally, we observe no spectral or kinetic differences by applying a bias voltage to the PEC cell, indicating that the effect of a voltage and the charge transfer processes between BiVO4 and the electrolyte occurs on longer time scales. Our results therefore provide new insights into the carrier dynamics of BiVO4 and further expand the application window of TAS as an analytical tool for photoanode materials.

The optical response of metallic nanostructures after intense excitation with femtosecond-laser pulses has recently attracted increasing attention: such response is dominated by ultrafast electron-phonon coupling and offers the possibility to achieve optical modulation with unprecedented terahertz bandwidth. In addition to noble metal nanoparticles, efforts have been made in recent years to synthesize heavily doped semiconductor nanocrystals so as to achieve a plasmonic behavior with spectrally tunable features. In this work, we studied the dynamics of the localized plasmon resonance exhibited by colloidal Cu(2-x)Se nanocrystals of 13 nm in diameter and with x around 0.15, upon excitation by ultrafast laser pulses via pump-probe experiments in the near-infrared, with ∼200 fs resolution time. The experimental results were interpreted according to the two-temperature model and revealed the existence of strong nonlinearities in the plasmonic absorption due to the much lower carrier density of Cu(2-x)Se compared to noble metals, which led to ultrafast control of the probe signal with modulation depth exceeding 40% in transmission.

We report a general computational model of complex material media for electrodynamics simulation using the Finite-Difference Time-Domain (FDTD) method. It is based on a multi-level multi-electron quantum system with electron dynamics governed by Pauli Exclusion Principle, state filling, and dynamical Fermi-Dirac Thermalization, enabling it to treat various solid-state, molecular, or atomic media. The formulation is valid at near or far off resonance as well as at high intensity. We show its FDTD application to a semiconductor in which the carriers' intraband and interband dynamics, energy band filling, and thermal processes were all incorporated for the first time. The FDTD model is sufficiently complex and yet computationally efficient, enabling it to simulate nanophotonic devices with complex electromagnetic structures requiring simultaneous solution of the mediumfield dynamics in space and time. Applications to direct-gap semiconductors, ultrafast optical phenomena, and multimode microdisk lasers are illustrated.

We investigate various ultrafast optical processes in ferromagnetic (III,Mn)V semiconductors induced by femtosecond laser pulses. Two-colour time-resolved magneto-optical spectroscopy has been developed, which allows us to observe a rich array of dynamical phenomena. We isolate several distinct temporal regimes in spin dynamics, interpreting the fast (<1 ps) dynamics as spin heating through sp–d exchange interaction between photo-carriers and Mn ions while the ∼100 ps component is interpreted as a manifestation of spin–lattice relaxation. Charge carrier and phonon dynamics were also carefully studied, showing an ultrashort charge lifetime of photo-injected electrons (∼2 ps) and propagating coherent acoustic phonon wavepackets with a strongly probe energy dependent oscillation period, amplitude and damping.

Abstract The subtitutional doping of 120‐Å‐ sized TiO 2 Particles with Fe( III )ions has a profound effect on the charge carrier recombination time in this colloidal semiconductor. In undoped particles, the mean lifetime of an electronhole pair is ca. 30 ± 15 ns. Doping with 0.5% Fe( III ) drastically augments the charge‐carrier lifetime which is extended to minutes or hours. The slow character of the recombination dynamics in Fe( III )‐doped colloids was confirmed by laser photolysis using the characteristic optical of electrons in TiO 2 to monitor the time course of the reaction. EPR studies showed the Fe( III ) ions to enter the host lattice on Ti( IV ) sites, charge compensation taking place through the formation of oxygen vacancies. Valence‐band holes produced under band‐gap excitation react with these centers it the bulk forming Fe( IV ), the conduction band electrons being trapped by Ti( IV ) at the particle surface. Presumably, the spatial separation of the trapped electron and hole sites inhibits their recombination.

Much effort has been devoted to the development of techniques to probe carrier dynamics, which govern many semiconductor device characteristics. We report direct imaging of electron dynamics on semiconductor surfaces by time-resolved photoemission electron microscopy using femtosecond laser pulses. The experiments utilized a variable-repetition-rate femtosecond laser system to suppress sample charging problems. The recombination of photogenerated electrons and the lateral motion of the electrons driven by an external electric field on a GaAs surface were visualized. The mobility was estimated from a linear relationship between the drift velocity and the potential gradient.

Forward Preface Contributors COMMON CONCEPTS Introduction General Vacuum Techniques Mass and Density Measurements Thermometry Symmetry in Crystallography Particle Scattering Sample Preparation for Metallography COMPUTATION AND THEORETICAL METHODS Introduction Introduction to Computation Summary of Electronic Structure Methods Prediction of Phase Diagrams Simulation of Microstructural Evolution Using the Field Method Bonding in Metals Binary and Multicomponent Diffusion Molecular-Dynamics Simulation of Surface Phenomena Simulation of Chemical Vapor Deposition Processes Magnetism in Alloys Kinematic Diffraction of X-Rays Dynamical Diffraction Computation of Diffuse Intensities in Alloys MECHANICAL TESTING Introduction Tension Testing High-Strain-Rate Testing of Materials Fracture Toughness Testing Methods Hardness Testing Tribological and Wear Testing THERMAL ANALYSIS Introduction Thermal Analysis - Definitions, Codes of Practice, and Nomenclature Thermogravimetric Analysis Differential Thermal Analysis and Differential Scanning Calorimetry Combustion Calorimetry Thermal Diffusivity by the Laser Flash Technique Simultaneous Techniques Including Analysis of Gaseous Products ELECTRICAL AND ELECTRONIC MEASUREMENT Introduction Conductivity Measurement Hall Effect in Semiconductors Deep-Level Transient Spectroscopy Carrier Lifetime: Free Carrier Absorption, Photoconductivity, and Photoluminescence Capacitance-Voltage (C-V) Characterization of Semiconductors Characterization of pn Junctions MAGNETISM AND MAGNETIC MEASUREMENT Introduction Generation and Measurement of Magnetic Fields Magnetic Moment and Magnetization Theory of Magnetic Phase Transitions Magnetometry Thermomagnetic Analysis Techniques to Measure Magnetic Domain Structures Magnetotransport in Metals and Alloys Surface Magneto-Optic Kerr Effect ELECTROCHEMICAL TECHNIQUES Introduction Cyclic Voltammetry Electrochemical Techniques for Corrosion Quantification Semiconductor Electrochemistry Scanning Electrochemical Microscopy The Quartz Crystal Microbalance in Electrochemistry OPTICAL IMAGING AND SPECTROSCOPY Introduction Optical Microscopy Reflected-Light Optical Microscopy Photoluminescence Spectroscopy Ultraviolet and Visible Absorption Spectroscopy Raman Spectroscopy of Solids Ultraviolet Photoelectron Spectroscopy Ellipsometry Impulsive Stimulated Thermal Scattering RESONANCE METHODS Introduction Nuclear Magnetic Resonance Imaging Nuclear Quadrupole Resonance Electron Paramagnetic Resonance Spectroscopy Cyclotron Resonance Mossbauer Spectrometry X-RAY TECHNIQUES Introduction X-Ray Powder Diffraction XAFS Spectroscopy X-Ray and Neutron Diffuse Scattering Measurements Resonant Scattering Techniques Magnetic X-Ray Scattering X-Ray Microprobe for Fluorescence and Diffraction Analysis X-Ray Magnetic Circular Dichroism Surface X-Ray Diffraction X-Ray Diffraction Techniques for Liquid Surfaces and Monomolecular Layers ELECTRON TECHNIQUES Introduction Scanning Electron Microscopy Transmission Electron Microscopy Scanning Transmission Electron Microscopy: Z-Contrast Imaging Scanning Tunneling Microscopy Low-Energy Electron Diffraction Energy-Dispersive Spectrometry Auger Electron Spectroscopy ION-BEAM TECHNIQUES Introduction High Energy Ion-Beam Analysis Elastic Ion Scattering for Composition Analysis Nuclear Reaction Analysis and Proton-Induced Gamma Ray Emission Particle-Induced X-Ray Emission Radiation Effects Microscopy Trace Element Accelerator Mass Spectrometry Introduction to Medium-Energy Ion Beam Analysis Medium-Energy Backscattering and Forward-Recoil Spectrometry Heavy-Ion Backscattering Spectrometry NEUTRON TECHNIQUES Introduction Neutron Powder Diffraction Single-Crystal Neutron Diffraction Phonon Studies Magnetic Neutron Scattering Appendices Index

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The coherent spin dynamics of resident carriers, electrons, and holes in semiconductor nanostructures is studied theoretically under the conditions of periodical optical excitation using short laser pulses and in an external magnetic field. The generation and dephasing of spin polarization in an ensemble of carrier spins, for which the relaxation time of individual spins exceeds the repetition period of the laser pulses, are analyzed. Accumulation of the spin polarization is manifested either as resonant spin amplification or as mode locking of carrier spin coherences. It is shown that both regimes have the same origin, while their appearance is determined by the optical pump power and the spread of spin precession frequencies in the ensemble.

We constructed an instrument for time-resolved photoemission electron microscopy (TR-PEEM) utilizing femtosecond (fs) laser pulses to visualize the dynamics of photogenerated electrons in semiconductors on ultrasmall and ultrafast scales. The spatial distribution of the excited electrons and their relaxation and/or recombination processes were imaged by the proposed TR-PEEM method with a spatial resolution about 100 nm and an ultrafast temporal resolution defined by the cross-correlation of the fs laser pulses (240 fs). A direct observation of the dynamical behavior of electrons on higher resistivity samples, such as semiconductors, by TR-PEEM has still been facing difficulties because of space and/or sample charging effects originating from the high photon flux of the ultrashort pulsed laser utilized for the photoemission process. Here, a regenerative amplified fs laser with a widely tunable repetition rate has been utilized, and with careful optimization of laser parameters, such as fluence and repetition rate, and consideration for carrier lifetimes, the electron dynamics in semiconductors were visualized. For demonstrating our newly developed TR-PEEM method, the photogenerated carrier lifetimes around a nanoscale defect on a GaAs surface were observed. The obtained lifetimes were on a sub-picosecond time scale, which is much shorter than the lifetimes of carriers observed in the non-defective surrounding regions. Our findings are consistent with the fact that structural defects induce mid-gap states in the forbidden band, and that the electrons captured in these states promptly relax into the ground state.

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PART 1. INTRODUCTION AND OVERVIEW 1. HOT ELECTRONS AND RELATED PHENOMENA: A BRIEF HISTORY - B K RIDLEY 2. MILESTONES OF HOT ELECTRON RESEARCH IN SEMICONDUCTORS - KARL HESS 3. GROWTH AND FABRICATION OF SEMICONDUCTOR DEVICES FOR HOT ELECTRON RESEARCH - J J HARRIS AND C T FOXON 4. OPTICAL SPECTROSCOPY AS A TOOL IN HOT ELECTRON STUDIES - JAGDEEP SHAH PART 2. ELECTRON PHONON INTERACTIONS 5. ENERGY AND MOMENTUM RELAXATION OF HOT ELECTRONS BY ACOUSTIC PHONON EMISSION - A J KENT 6. SCATTERING OF ELECTRONS BY OPTICAL MODES IN BULK SEMICONDUCTORS AND QUANTUM WELLS - M BABIKER AND N ZAKHLENIUK 7. PHONON EMISSION AND ABSORPTION BY HOT ELECTRONS IN (-DOPED MULTIPLE LAYERS IN GAAS - M ASCHE 8. ULTRAFAST SPECTROSCOPY OF LOW DIMENSIONAL STRUCTURES - JOHN F RYAN 9. IMPACT PHENOMENA AND NONLINEAR SPATIO-TEMPORAL DYNAMICS OF HOT ELECTRONS IN SEMICONDUCTORS - ECKHARD SCHOLL 10. NON-EQUILIBRIUM PHONONS AND INSTABILITIES IN QUANTUM WELLS - N BALKAN PART 3. QUANTUM WELLS AND DOTS 11. CARRIER RELAXATION IN 1-D AND 0-D - C M SOTOMAYOR TORRES 12. ENERGY AND MOMENTUM RELAXATION OF HOT ELECTRONS IN LONG QUANTUM WIRES - ROBERTO CINGOLANI 13. ELECTRON PHONON INTERACTIONS IN ELECTRON TRANSFER DEVICES AND IN QUASI 1-D STRUCTURES - NABUHIKO SAWAKI PART 4. HOT ELECTRON TUNNELLING 14. ASPECTS OF TUNNELLING PHENOMENA IN NON-EQUILIBRIUM TRANSPORT - J R BARKER 15. PLASMON EXCITATION EFFECTS IN RESONANT TUNNELLING - L EAVES 16. HOT ELECTRONS AND SPACE CHARGE WAVES IN SUPERLATTICES - H T GRAHN PART 5. HOT ELECTRON DEVICES 17. HOT ELECTRONS IN SEMICONDUCTOR DEVICES - SERGE LURYI 18. MOTE CARLO SIMULATION OF HOT ELECTRONS IN SEMICONDUCTOR DEVICES - C JACOBONI, A ABRAMO AND R BRUNETTI 19. HOT ELECTRON EFFECTS IN QUANTUM WELL LASERS AND THE TUNNELLING INJECTION LASER - P K BHATTACHARAYA 20. ELECTROLUMINESCENCE BY IMPACT IONIZATION OF IMPURITIES IN SEMICONDUCTORS - GAETANO SCAMARCIO AND FREDERICO CAPASSO 21. HOT ELECTRONS IN N-I-P-I BASED DEVICES - G H DOHLER, J HEBER, M PETER, S ECKL, S MALZER, A FORSTER AND H LUTH

One-dimensional nanostructures of metal oxide semiconductors have both potential and demonstrated applications for use in light waveguides, photodetectors, solar energy conversion, photocatalysis, etc. We investigated the transport and reaction dynamics of the photogenerated charge carriers in individual titania nanowires using single-particle photoluminescence (PL) spectroscopy. Examination of the spectral and kinetic characteristics revealed that the photoluminescence bands originating from defects in the bulk and/or on the surface appeared in the visible region with numerous photon bursts by photoirradiation using a 405-nm laser under an Ar atmosphere. From the single-molecule kinetic analysis of the bursts, it was found that the quenching reaction of trapped electrons by molecular oxygen follows a Langmuir-Hinshelwood mechanism. In addition, a novel spectroscopic method, i.e., single-molecule spectroelectrochemistry, was utilized to explore the nature of the defect states inherent in the wires. The spatially resolved PL imaging techniques thus enable us to ascertain the location of the luminescent active sites that are related to the heterogeneously distributed defects and to present experimental evidence of the long-distance transport of charge carriers in the wire. Consequently, this study provides a great opportunity to understand the role of defects in the behavior of charge carriers in TiO(2) nanomaterials with various morphologies.

In order to exploit the intriguing optical properties of graphene it is essential to gain a better understanding of the light-matter interaction in the material on ultrashort timescales. Exciting the Dirac fermions with intense ultrafast laser pulses triggers a series of processes involving interactions between electrons, phonons and impurities. Here we study these interactions in epitaxial graphene supported on silicon carbide (semiconducting) and iridium (metallic) substrates using ultrafast time- and angle-resolved photoemission spectroscopy (TR-ARPES) based on high harmonic generation. For the semiconducting substrate we reveal a complex hot carrier dynamics that manifests itself in an elevated electronic temperature and an increase in linewidth of the π band. By analyzing these effects we are able to disentangle electron relaxation channels in graphene. On the metal substrate this hot carrier dynamics is found to be severely perturbed by the presence of the metal, and we find that the electronic system is much harder to heat up than on the semiconductor due to screening of the laser field by the metal.

We propose a theory of optically induced currents in dielectrics and wide gap semiconductors exposed to a nonresonant ultrashort laser pulse with a stabilized carrier-envelope phase. To describe strong-field electron dynamics, equations for the density matrix have been solved self-consistently with equations for the macroscopic electric field inside the medium, which we model by a one-dimensional potential. We provide a detailed analysis of physically important quantities (band populations, macroscopic polarization, and transferred charge), which reveals that carrier-envelope phase control of the electric current can be interpreted as a result of quantum-mechanical interference of multiphoton excitation channels. Our numerical results are in good agreement with experimental data.

Recombination processes in rare-earth metals in semiconductors are a special case due to the localized nature of $f$ electrons. Our work explores in detail the radiative and nonradiative mechanisms of energy transfer for erbium in silicon by investigating the temperature dependence of the intensity and the decay time of the photoluminescence of Er-related centers in Si. We show that nonradiative energy back transfer from the excited Er $4f$ shell causes luminescence quenching below 200 K. We study electroluminescence decay by applying different bias conditions during the decay. In a two-beam experiment the photoluminescence decay is monitored for different background-excitation laser powers. Changes in the decay time are strong evidence of the impurity Auger effect as an efficient luminescence-quenching mechanism for Er in Si. A fast initial luminescence decay component at high pumping powers is related to quenching by excess carriers. The power dependence, the decay-time components, and the two-beam experiment are simulated by a set of rate equations which involve the formation of excitons, a decrease of the pumping efficiency by exciton Auger recombination, and a decrease of radiative efficiency by the impurity Auger effect with free electrons. As a nonradiative deexcitation path competing with spontaneous emission, the impurity Auger effect decreases the excited-state lifetime of Er in Si, and dominates the thermal quenching of luminescence in the temperature range from 4 to 100 K. We find that the decrease of emission intensity above 100 K is caused by an unidentified second back-transfer process.

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Abstract Lithography is one of the most widely used methods for cutting‐edge research and industrial applications, mainly owing to its ability to draw patterns in the micro and even nanoscale. However, the fabrication of semiconductor micro/nanostructures via conventional electron or optical lithography technologies often requires a time‐consuming multistep process and the use of expensive facilities. Herein, a low‐cost, high‐resolution, facile, and versatile direct patterning method based on metal–organic molecular precursors is reported. The ink‐based metal–organic precursors are found to operate as negative resists, with the material exposed by different methods (electron‐beam/laser/heat/ultraviolet (UV)) to render them insoluble in the development process. This technical process can deliver metal chalcogenide semiconductors with arbitrary 2D/3D patterns with sub‐50 nm resolution. Electron beam lithography, two‐photon absorption lithography, thermal scanning probe lithography, and UV photolithography are demonstrated for the direct patterning process. Different metal chalcogenide semiconductor nanodevices, such as photoconductive selenium‐doped Sb 2 S 3 nanoribbons, p‐type PbS single‐nanowire field‐effect transistors, and p‐n junction CdS/Cu 2 S nanowire solar cells, are fabricated by this method. This direct patterning technique is a versatile and simple micro/nanolithography technology with considerable potential for “lab‐on‐a‐chip” preparation of semiconductor devices.

Preface to the First Edition Preface to the Second Edition INTRODUCTION Arrhenius Plot The Relationship between Kinetics and Thermodynamics The Boltzmann Distribution Kinetic Theory of Gases Collisions DIFFUSION IN FLUIDS Diffusion in a Gas Diffusion in Liquids DIFFUSION IN AMORPHOUS MATERIALS Amorphous Materials Network Glass Formers The Glass Transition The Free Volume Model Fictive Temperature Diffusion in Polymers The Stokes-Einstein Relationship DIFFUSION IN CRYSTALS Diffusion in a Crystal Diffusion Mechanisms in Crystals Equilibrium Concentration of Vacancies Simmons and Balluffi Experiment Ionic and Covalent Crystals Stoichiometry Measurement of Diffuion Coefficients Surface Diffusion Diffusion in Grain Boundaries Kirkendall Effect Whisker Growth Electromigration DIFFUSION IN SEMICONDUCTORS Introduction Diffusion in Silicon Diffusion of Zinc in GaAs Recombination Enhanced Diffusion Doping of Semiconductors Point Defect Generation in Silicon during Crystal Growth Migration of Interstitials (and Liquid Droplets) in a Temperature Gradient Oxygen in Silicon Gettering Solid-State Doping ION IMPLANTATION Introduction Ion Interactions Implantation Damage Rutherford Backscattering Channeling Silicon-on-Insulator MATHEMATICS OF DIFFUSION Random Walk The Diffusion Equation Solutions to the Diffusion Equation Numerical Methods Boltzmann-Matano Analysis Diffusion During Phase Separation STEFAN PROBLEMS Steady State Solutions to the Diffusion Equation Deal-Grove Analysis Diffusion Controlled Growth of a Spherical Precipitate Diffusion Limited Growth in Cylindrical Coordinates Diffuion Controlled Growth of a Precipitate PHASE TRANSFORMATIONS Transformation Rate Limited Growth Diffuion Limited Growth Thermally Limited Growth Casting of Metals Operating Point CRYSTAL GROWTH METHODS Melt Growth Solution Growth Vapor Phase Growth Stoichiometry SEGREGATION Segregation During a Phase Change Lever Rule Scheil Equation Zone Refining Diffusion at a Moving Interface Segregation in Three Dimensions Burton, Primm and Schlicter Analysis INTERFACE INSTABILITIES Constitutional Supercooling Mullins and Sekerka Linear Instability Analysis Anisotropic INterface Kinetics CHEMICAL REACTION RATE THEORY The Equilibrium Constant Reaction Rate Theory Reaction Rate Constant Transition State Theory Experimental Determination of the Order of a Reaction Net Rate of Reaction Catalysis Quasi-Equilibrium Model for the Rate of a First Order Phase Change PHASE EQUILIBRIA First Order Phase Changes Second Order Phase Changes Critical Point Between Liquid and Vapor NUCLEATION Homogenous Nucleation Heterogeneous Nucleation Johnson-Mehl-Avrami Equation SURFACE LAYERS Langmuir Adsorption CVD Growth by a Surface Decomposition Reaction Langmuir-Hinschelwood Reaction Surface Nucleation Thin Films Surface Reconstruction Amorphous Deposits Surface Modification Fractal Deposits Strain Energy and Misfit Dislocations Strained Layer Growth THIN FILM DEPOSITION Liquid Phase Epitaxy Growth Configuration for LPE Chemical Vapor Deposition Metal-Organic Chemical Vapor Deposition Physical Vapor Deposition Sputter Deposition Metallization Laser Ablation Molecular Beam Epitaxy Atomic Layer Epitaxy PLASMAS Direct Current (DC) Plasmas Radio Frequency Plasmas Plasma Etching Plasma Reactors Magnetron Sputtering Electron Cyclotron Resonance Ion Milling RAPID THERMAL PROCESSING Introduction Rapid Thermal Processing Equipment Radiative Heating Temperature Measurement Thermal Stress Laser Heating KINETICS OF FIRST ORDER PHASE TRANSFORMATIONS General Considerations The Macroscopic Shape of Crystals General Equation for the Growth Rate of Crystals Kinetic Driving Force Vapor Phase Growth Melt Growth Molecular Dynamics Studies of Melt Crystallization Kinetics The Kossel-Stranski Model Nucleation of Layers Growth on Screw Dislocations The Fluctuation Dissipation Theorem THE SURFACE ROUGHENING TRANSITION Surface Roughness The Ising Model Cooperative Processes Monte Carlo Simulations of Crystallization Equilibrium Surface Structure Computer Simulations Growth Morphologies Kinetic Roughening Polymer Crystallization ALLOYS: THERMODYNAMICS AND KINETICS Crystallization of Alloys Phase Equilibria Regular Solution Model Near Equilibrium Conditions Phase Diagrams The DLP Model PHASE SEPARATION AND ORDERING Phase Separation versus Ordering Phase Separation The Spinodal in a Regular Solution Analytical Model for Diffusion during Spinodal Decomposition Microstructure Development Modeling of Phase Separation and Ordering NON-EQUILIBRIUM CRYSTALLIZATION OF ALLOYS Non Equilibrium Crystallization Experiment Computer Modeling Analytical Model Comparison with Experiment Crystallization of Glasses COARSENING, RIPENING Coarsening Free Energy of a Small Particle Coarsening in a Solution Coarsening of Dendritic Structures Sintering Bubbles Grain Boundaries Scrath Smoothing DENDRITES Dendritic Growth Conditions for Dendritic Growth Simple Dendrite Model Phase Field Modeling Faceted Growth Distribution Coefficient EUTECTICS Eutectic Phase Diagram Classes of Eutectic Microstructures Analysis of Lamellar Eutectics Off-Composition Eutectics Coupled Growth Third Component Elements CASTINGS Grain Structure of Castings Dendrite Re-Melting

The unique electronic properties of the surface electrons in a topological insulator are protected by time-reversal symmetry. Circularly polarized light naturally breaks time-reversal symmetry, which may lead to an exotic surface quantum Hall state. Using time- and angle-resolved photoemission spectroscopy, we show that an intense ultrashort midinfrared pulse with energy below the bulk band gap hybridizes with the surface Dirac fermions of a topological insulator to form Floquet-Bloch bands. These photon-dressed surface bands exhibit polarization-dependent band gaps at avoided crossings. Circularly polarized photons induce an additional gap at the Dirac point, which is a signature of broken time-reversal symmetry on the surface. These observations establish the Floquet-Bloch bands in solids and pave the way for optical manipulation of topological quantum states of matter.

Ceramics and semiconductors are hard, strong, inert and lightweight. They also have good optical properties, wide energy bandgap and high maximum current density. This combination of properties makes them ideal candidates for tribological, semiconductor, MEMS and optoelectronic applications respectively. Manufacturing these materials without causing surface and subsurface damage is extremely challenging due to their high hardness, brittle characteristics and poor machinability. However, ductile regime machining of these materials is possible due to the high-pressure phase transformation occurring in the material caused by the high compressive stresses induced by the single point diamond tool tip. In this study, to further augment the ductile response of the machined material, single point scratch tests are coupled with a micro-laser assisted machining (μ-LAM) technique. The high pressure phase is preferentially heated and thermally softened by using concentrated energy sources (i.e. laser beams) to enhance the ductile response of the material. The focus here is to develop an efficient manufacturing technique to improve the surface quality of ceramics and semiconductors to be used as optical devices (mirrors and windows). Machining parameters such as the depth of cut, feed, cutting speed and laser power are optimized in order to make the manufacturing process more time and cost effective. Also, the science behind the thermal softening effect during the formation of high-pressure phases is experimentally studied by isolating the temperature and pressure effect. Micro-laser assisted scratch tests successfully demonstrate the enhanced thermal softening in silicon (Si), silicon carbide (SiC) and sapphire resulting in greater depths of cuts (when compared to similar applied loads for cuts with no laser), greater ductile-to-brittle transition depths and smaller cutting forces. Imaging and characterization techniques such as optical microscopy, light interferometry, XRD, surface profilometry, OIM, AFM, scanning acoustic microscopy, electron microscopy and Raman spectroscopy are utilized to quantify the ductile mode material removal process. Ductile mode machining is experimented on nine ceramics and semiconductors including Si, SiC (three polytypes: 4H, 6H and 3C), sapphire, quartz, spinel, AlON and AlTiC.

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Historical Overview. First ages of the coherent electromagnetic waves generation applied to new materials transfer processes named laser ablation (J.-F. Eloy). I. Mechanisms, Spectroscopy and Diagnostics. Electron emission by laser irradiated surfaces (G. Petite et al.). Laser-ablation: Fundamentals and recent developments (D. Bauerle et al.). Laser ablation of solids: Basic principles and physical effects (M. von Allmen). Comparison of the ablation of dielectrics and metals at high and low laser powers (R.W. Dreyfus). Effects of ambient background gases on YBCO plume propagation under film growth conditions: Spectroscopic, ion probe, and fast photographic studies (D.B. Geohegan). Picosecond laser ablation of mono and multicomponent targets (W. Marine et al.). Laser ablation dynamics of superconductors: Photoacoustic and spectroscopic studies (P.E. Dyer et al.). Creation mechanism of a laser-plasma in front of a solid in an ambient gas (C. Boulmer-Leborgne et al.). Dynamics of laser ablation of high Tc superconductors and semiconductors and a new method for growth of films (K. Murakami). Plasma formation from laser-target interaction Basic phenomena and applications to superconducting thin film deposition (C. Champeaux et al.). Analytical tools using laser ablation (J.F. Muller et al.). II. Laser Ablation and Etching. Ultraviolet laser interactions with polymer surfaces in the microsecond regime: The photokinetic effect (R. Srinivasan). Surface modification of polymers with excimer lasers and its applications (A. Yabe, H. Niino). 248 nm laser ablation of chlorinated copper and CuCl surfaces (S. Kuper et al.). Surface modification of polymers and ceramics induced by excimer laser radiation (D.W. Thomas et al.). Polishing of diamond films by light (V.N. Tokarev et al.). Laser ablation and laser etching (J. Boulmer et al.). Excimer laser projector for materials processing applications (M.C. Gower, P.T. Rumsby). III. Thin Film Deposition and Materials Synthesis. Laser ablation synthesis and properties of epitaxial superconducting superlattices (D.H. Lowndes et al.). In-situ preparation of High thin films by pulsed laser deposition (H.-U. Habermeier). Laser ablation of BiSrCaCuO films (J. Perriere). Characterization of thin films of superconducting BiSrCaCuO and YBaCuO produced by laser ablation and spectroscopic analysis of intermediate species (A. Giardini Guidoni et al.). Growth of YBCO superconducting thin films (D. Chambonnet et al.). The unique applications of pulsed laser deposition to the epitaxial growth of semiconductor films (J.T. Cheung, H. Sankur). Laser ablation for the synthesis of oxides (F. Beech et al.). Influence of ambient gas and substrate temperature in preparation of silicon dioxide films by laser ablation (A. Slaoui et al.).

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PHYSICAL DEPOSITION TECHNIQUES Thermal Evaporation (Coordinating Editors: E.B. Graper and J. Vossen) Introduction and general discussion (E.B. Graper) Resistance evaporation (E.B. Graper) Electron beam evaporation (E.B. Graper) Ion vapor evaporation (E.B. Graper) Cathodic arc deposition (P.J. Martin) Laser ablation (A. Morimoto and T. Shimizu) Molecular Beam Epitaxy (Coordinating Editors: S.A. Barnett and J. Poate) Introduction and general discussion (S.A. Barnett and I.T. Ferguson) Semiconductor growth by metalorganic molecular beam epitaxy (MOMBE) (C.R. Abernathy) Gas-source MBE (G.Y. Robinson) Chemical beam epitaxy (T.H. Chiu) Thin film deposition and dopant incorporation by energetic particle sources (S. Strite and H. Morkoc) Sputtering (Coordinating Editors: S.I. Shah and D. Glocker) Introduction and general discussion (S.I. Shah) Glow discharge sputtering (A.S. Penfold) Magneton sputtering (A.S. Penfold) Ion-beam sputtering (T. Itoh) Thermal Spraying (Coordinating Editor: R.C. Tucker Jr.) Introduction to thermal spray coatings (R.C. Tucker Jr.) Flame spray (P.A. Kammer) Plasma spray coatings (R.C. Tucker Jr.) High velocity oxy-fuel coatings (R.C. Tucker Jr.) Detonation gun deposition (R.C. Tucker Jr.) Mechanical, wear, corrosion, and other properties of thermal spray coatings (R.C. Tucker Jr.) CHEMICAL DEPOSITION TECHNIQUES Chemical Vapor Deposition (Coordinating Editor: L. Vescan) Introduction and general discussion (L. Vescan) Metalorganic chemical vapour deposition (MOCVD) (R.D. Dupuis) Photoassisted chemical vapour deposition (S.J.C. Irvine) Thermally activated chemical vapour deposition (L. Vescan) Atomic layer epitaxy (T. Suntola) PROCESSING TECHNOLOGIES Pattern Transfer (Coordinating Editor: J.W. Coburn Introduction and general discussion (J.W. Coburn) Reactive ion etching (C. Steinbruchel) Ion-beam-based chemical dry etching (C. Steinbruchel) Ion milling (C. Steinbruchel) REAL-TIME DIAGNOSTICS Introduction and General Discussion (Coordinating Editor: R.W. Collins) Diagnostic Techniques Reflection high-energy electron diffraction as a diagnostic technique (B.A. Joyce) Low-energy electron diffraction (Sheng-Liang Chang and P.A. Thiel) Reflection mass spectroscopy (R. Kaspi) Optical Diagnostics Infrared emission interferometry (A.J. Springthorpe) Reflectance anisotropy (B. Drevillon) Interferometry as an in situ probe during processing of semiconductor wafers (V.M. Donnelly) Ellipsometry (P. Snyder) Photoluminescence (P.R. Berger) Elastic laser light scattering (B. Gallois) Plasma Probes Langmuir probe diagnostics (N. Hershkowitz) Microwave interferometers (R.A. Breun) Atomic absorption spectroscopy (Chih-shun Lu) Other Diagnostics (Coordinating Editor: R. Collins) Quartz monitors and microbalances (J. Krim and C. Daly) Probes of film stress (D. Glocker) SURFACE MODIFICATION IN VACUUM Processes for Substrate Cleaning (D. Mattox) Surface Treatment for Corrosion and Wear Protection Material aspects of corrosion protection (Cathy Cotell) Ion implantation with beams (Mike Nastasi) Plasma source ion implantation (Donald Rej) Surface Treatment of Polymers for Adhesion Plasma sources for polymer surface treatment (M.R. Wertheimer and Edward Liston) Surface chemistry of treated polymers (Lou Gerenser) MATERIALS Hard and Protective Materials Introduction (O. Knotek and A. Schrey) TiN TiAIN TiAIVN CrN ZrN HfN BN Diamond Ni-Cr-B-Si Al-bronze Al2O3-TiO2 Electronic Materials Introduction (K. Cadien and S. Sivaram) GaAs a-Si:H AlGaAs Tellurides CuInSe2 Si Ge Si-Ge W GaN AIN ErAs Quaternaries Silicides SiSnC SiN Optical Materials Introduction (J. Targove) AIN ZnO PbTiO3 KNbO3 Ferroelectric Materials Introduction (M. Sayer) Bi4Ti3O12 LiNbO3 and LiTaO3 PbTiO3/PbZrTiO3 Ferromagnetic Materials Introduction (E.M.T. Velu and D.N. Lambeth) CoCr TbFeCo CoPt/CoPd GdTbFe Superconducting Materials Introduction (J. Azoulay) NbN YBa2Cu3O7 Thallium-based compounds Mercury-based compounds Miscellaneous Materials PTFE PPN Ir/Pt Appendix A: List of Contributors Subject Index

Diamond is a wide bandgap semiconductor with excellent physical properties which allow it to operate under extreme conditions. However, the technological use of diamond was mostly conceived for the fabrication of ultraviolet, ionizing radiation and nuclear detectors, of electron emitters, and of power electronic devices. The use of nanosecond pulse excimer lasers enabled the microstructuring of diamond surfaces, and refined techniques such as controlled ablation through graphitization and etching by two-photon surface excitation are being exploited for the nanostructuring of diamond. On the other hand, ultrashort pulse lasers paved the way for a more accurate diamond microstructuring, due to reduced thermal effects, as well as an effective surface nanostructuring, based on the formation of periodic structures at the nanoscale. It resulted in drastic modifications of the optical and electronic properties of diamond, of which “black diamond” films are an example for future high-temperature solar cells as well as for advanced optoelectronic platforms. Although experiments on diamond nanostructuring started almost 20 years ago, real applications are only today under implementation.

Current mechanical wafer dicing process adopting diamond grit shows advantages of low cost and high productivity. However, mechanical process for ultra-thin wafers would induce residual stress or mechanical damage, which can lead to wafer broken and die cracking. With the development of laser technology, laser precision micromachining has been employed for thin semiconductor wafer singulation, which shows advantages of no chipping, small kerf width, and high throughput over mechanical blade dicing. However, thermal damage to the chip induced by laser ablation results in die strength degradation. For ultra thin chip, low die strength tends to induce die crack in packaging process. Thus, thermal damage to the chip needs to be studied. In this study, first we made a comparison between mechanical blade sawing and laser ablation processes. Die strength and microstructure changes were studied by means of bending test and transmission electron microscope (TEM) analysis, respectively. Die strength results showed that the die strength obtained by laser dicing was far lower than that obtained by blade sawing. TEM analysis demonstrated that formation of microcracks and porosities in laser diced face, caused the die strength degradation. In addition, significant deviation between frontside and backside die strength was found in the laser micromachinned dies. The reason for this deviation was clarified as the defects density difference existing in top and bottom layer of the chip sidewalk Experiments results showed that the die strength obtained by laser dicing can not meet the demand of the packaging process. It tends to crack or fracture in the die attach or wire bonding process. Thus, it is essential to improve the die strength. Thus, in this investigation, etching processes including wet-etch and dry-etch were attempted to recover the die strength by removing the chip side wall damage. SEM and TEM images indicated that, before etching, the laser diced side walls were with rough surfaces, voids and microcracks. After etching, the surfaces got smooth and most of the voids and microcracks were removed. Chip strength measurement also verified the partial die strength recovery after etching process.

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Ion acceleration driven by superintense laser pulses is attracting an impressive and steadily increasing effort. Motivations can be found in the applicative potential and in the perspective to investigate novel regimes as available laser intensities will be increasing. Experiments have demonstrated, over a wide range of laser and target parameters, the generation of multi-MeV proton and ion beams with unique properties such as ultrashort duration, high brilliance, and low emittance. An overview is given of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives. The main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described.

Semiconductor nanowires (NWs) represent a new class of materials and a shift from conventional two-dimensional bulk thin films to three-dimensional devices. Unlike thin film technology, lattice mismatch strain in NWs can be relaxed elastically at the NW free surface without dislocations. This capability can be used to grow unique heterostructures and to grow III-V NWs directly on inexpensive substrates, such as Si, rather than lattice-matched but more expensive III-V substrates. This capability, along with other unique properties (quantum confinement and light trapping), makes NWs of great interest for next generation optoelectronic devices with improved performance, new functionalities, and reduced cost. One of the many applications of NWs includes energy conversion. This review will outline applications of NWs in photovoltaics, thermoelectrics, and betavoltaics (direct conversion of solar, thermal, and nuclear energy, respectively, into electrical energy) with an emphasis on III-V materials. By transitioning away from bulk semiconductor thin films or wafers, high efficiency photovoltaic cells comprised of III-V NWs grown on Si would improve performance and take advantage of cheaper materials, larger wafer sizes, and improved economies of scale associated with the mature Si industry. The thermoelectric effect enables a conversion of heat into electrical power via the Seebeck effect. NWs present an opportunity to increase the figure of merit (ZT) of thermoelectric devices by decreasing the thermal conductivity (κ) due to surface phonon backscattering from the NW surface boundaries. Quantum confinement in sufficiently thin NWs can also increase the Seebeck coefficient by modification of the electronic density of states. Prospects for III-V NWs in thermoelectric devices, including solar thermoelectric generators, are discussed. Finally, betavoltaics refers to the direct generation of electrical power in a semiconductor from a radioactive source. This betavoltaic process is similar to photovoltaics in which photon energy is converted to electrical energy. In betavoltaics, however, energetic electrons (beta particles) are used instead of photons to create electron-hole pairs in the semiconductor by impact ionization. NWs offer the opportunity for improved beta capture efficiency by almost completely surrounding the radioisotope with semiconductor material. Improving the efficiency is important in betavoltaic design because of the high cost of materials and manufacturing, regulatory restrictions on the amount of radioactive material used, and the enabling of new applications with higher power requirements.

The ultrashort-laser photoexcitation and structural modification of buried atomistic optical impurity centers in crystalline diamonds are the key enabling processes in the fabrication of ultrasensitive robust spectroscopic probes of electrical, magnetic, stress, temperature fields, and single-photon nanophotonic devices, as well as in "stealth" luminescent nano/microscale encoding in natural diamonds for their commercial tracing. Despite recent remarkable advances in ultrashort-laser predetermined generation of primitive optical centers in diamonds even on the single-center level, the underlying multi-scale basic processes, rather similar to other semiconductors and dielectrics, are almost uncovered due to the multitude of the involved multi-scale ultrafast and spatially inhomogeneous optical, electronic, thermal, and structural elementary events. We enlighten non-linear wavelength-, polarization-, intensity-, pulsewidth-, and focusing-dependent photoexcitation and energy deposition mechanisms in diamonds, coupled to the propagation of ultrashort laser pulses and ultrafast off-focus energy transport by electron-hole plasma, transient plasma- and hot-phonon-induced stress generation and the resulting variety of diverse structural atomistic modifications in the diamond lattice. Our findings pave the way for new forthcoming groundbreaking experiments and comprehensive enlightening two-temperature and/or atomistic modeling both in diamonds and other semiconductor/dielectric materials, as well as innovative technological breakthroughs in the field of single-photon source fabrication and "stealth" luminescent nano/microencoding in bulk diamonds for their commercial tracing.