The emergence of highly efficient short-wavelength laser diodes based on the III-V compound semiconductor GaN has not only enabled high-density optical data storage, but is also expected to revolutionize display applications. Moreover, a variety of scientific applications in biophotonics, materials research and quantum optics can benefit from these versatile and cost-efficient laser light sources in the near-UV to green spectral range. This thesis describes the device physics of GaN-based laser diodes, together with recent efforts to achieve longer emission wavelengths and short-pulse emission. Experimental and theoretical approaches are employed to address the individual device properties and optimize the laser diodes toward the requirements of specific applications.

This book provides for the first time a good understanding of the etching profile technologies that do not disturb the plasma. Three types of sensors are introduced: on-wafer UV sensors, on-wafer charge-up sensors and on-wafer sheath-shape sensors in the plasma processing and prediction system of real etching profiles based on monitoring data. Readers are made familiar with these sensors, which can measure real plasma process surface conditions such as defect generations due to UV-irradiation, ion flight direction due to charge-up voltage in high-aspect ratio structures and ion sheath conditions at the plasma/surface interface. The plasma etching profile realistically predicted by a computer simulation based on output data from these sensors is described.

stacked QD structure and is useful for examining the possibility of all optical measurement of stacked QD layers. Optical absorption spectra of self-assembled QDs has been little reported, and further investigation in necessary to study hole-burning memory. 2.5 Summary This chapter describes recent advances in quantum dot fabrication tech nologies, focusing on our self-formed quantum dot technologies including TSR quantum dots and SK-mode self-assembled quantum dots. As is described in this chapter, there are many possible device applications such as quantum dot tunneling memory devices, quantum dot fioating-dot gate FETs, quantum dot lasers, and quantum dot hole-burning memory devices. The quantum dot laser applications seem to be the most practicable among these applications. However, many problems remain to be solved before even this application becomes practical. The most important issue is to of self-assembled quantum dots more pre control the size and position cisely, with an accuracy on an atomic scale. The confinement must be enough to keep the separation energy between quantized energy levels high enough to get high-temperature characteristics. The lasing oscillation frequency should be fixed at 1.3 f.lITl or 1.5 f.lITl for optical communication. Phonon bottleneck problems should be solved by the optimization of device structures. Fortunately, there is much activity in the area of quantum dot lasers and, therefore, many breakthroughs will be made, along with the exploration of other new application areas.

Recent advances in the fabrication of semiconductors have created almost un limited possibilities to design structures on a nanometre scale with extraordinary electronic and optoelectronic properties. The theoretical understanding of elec trical transport in such nanostructures is of utmost importance for future device applications. This represents a challenging issue of today's basic research since it requires advanced theoretical techniques to cope with the quantum limit of charge transport, ultrafast carrier dynamics and strongly nonlinear high-field ef fects. This book, which appears in the electronic materials series, presents an over view of the theoretical background and recent developments in the theory of electrical transport in semiconductor nanostructures. It contains 11 chapters which are written by experts in their fields. Starting with a tutorial introduction to the subject in Chapter 1, it proceeds to present different approaches to transport theory. The semiclassical Boltzmann transport equation is in the centre of the next three chapters. Hydrodynamic moment equations (Chapter 2), Monte Carlo techniques (Chapter 3) and the cellular au tomaton approach (Chapter 4) are introduced and illustrated with applications to nanometre structures and device simulation. A full quantum-transport theory covering the Kubo formalism and nonequilibrium Green's functions (Chapter 5) as well as the density matrix theory (Chapter 6) is then presented.

During a century, from the Van der Waals mean field description (1874) of gases to the introduction of renormalization group (RG techniques 1970), thermodynamics and statistical physics were just unable to account for the incredible universality which was observed in numerous critical phenomena. The great success of RG techniques is not only to solve perfectly this challenge of critical behaviour in thermal transitions but to introduce extremely useful tools in a wide field of daily situations where a system exhibits scale invariance. The introduction of scaling, scale invariance and universality concepts has been a significant turn in modern physics and more generally in natural sciences. Since then, a new "physics of scaling laws and critical exponents", rooted in scaling approaches, allows quantitative descriptions of numerous phenomena, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos and turbulence. The chapters are jointly written by an experimentalist and a theorist. This book aims at a pedagogical overview, offering to the students and researchers a thorough conceptual background and a simple account of a wide range of applications. It presents a complete tour of both the formal advances and experimental results associated with the notion of scaling, in physics, chemistry and biology.

This book presents the fabrication of optoelectronic nanodevices. The structures considered are nanowires, nanorods, hybrid semiconductor nanostructures, wide bandgap nanostructures for visible light emitters and graphene. The device applications of these structures are broadly explained. The book deals also with the characterization of semiconductor nanostructures. It appeals to researchers and graduate students.

This monograph solely presents the Fowler-Nordheim field emission (FNFE) from semiconductors and their nanostructures. The materials considered are quantum confined non-linear optical, III-V, II-VI, Ge, Te, carbon nanotubes, PtSb2, stressed materials, Bismuth, GaP, Gallium Antimonide, II-V, Bi2Te3, III-V, II-VI, IV-VI and HgTe/CdTe superlattices with graded interfaces and effective mass superlattices under magnetic quantization and quantum wires of the aforementioned superlattices. The FNFE in opto-electronic materials and their quantum confined counterparts is studied in the presence of light waves and intense electric fields on the basis of newly formulated electron dispersion laws that control the studies of such quantum effect devices. The importance of band gap measurements in opto-electronic materials in the presence of external fields is discussed from this perspective. This monograph contains 200 open research problems which form the very core and are useful for Ph. D students and researchers. The book can also serve as a basis for a graduate course on field emission from solids.

The introduction of GaAs/ AIGaAs double heterostructure lasers has opened the door to a new age in the application of compound semiconductor materials to microwave and optical technologies. A variety and combination of semiconductor materials have been investigated and applied to present commercial uses with these devices operating at wide frequencies and wavelengths. Semiconductor modulators are typical examples of this technical evolutions and hsve been developed for commercial use. Although these have a long history to date, we are not aware of any book that details this evolution. Consequently, we have written a book to provide a comprehensive account of semiconductor modulators with emphasis on historical details and experimantal reports. The objective is to provide an up-to-date understanding of semiconductor modulators. Particular attention has been paid to multiple quantum well (MQW) modulators operating at long wavelengths, taking into account the low losses and dispersion in silica fibers occuring at around 1.3 and 1.55 mm. At the present time, MQW structures have been investigated but these have not been sufficiently developed to provide characteristic features which would be instructive enough for readers. One problem is the almost daily publication of papers on semiconductor modulators. Not only do these papers provide additional data, but they often modify the interpretations of particular concepts. Almost all chapters refer to the large number of published papers that can be consulted for future study.

Reflection high-energy electron diffraction (RHEED) is the analytical tool of choice for characterizing thin films during growth by molecular beam epitaxy, since it is very sensitive to surface structure and morphology. This book serves as an introduction to RHEED for beginners and describes detailed experimental and theoretical treatments for experts, explaining how to analyze RHEED patterns. For beginners the principles of electron diffraction are explained and many examples of the interpretation of RHEED patterns are described. The second part of the book contains detailed descriptions of RHEED theory. The third part applies RHEED to the determination of surface structures, gives detailed descriptions of the effects of disorder, and critically reviews the mechanisms contributing to RHEED intensity oscillations. This unified and coherent account will appeal to both graduate students and researchers in the study of molecular beam epitaxial growth.

This book is dedicated to the analysis of parametric amplification with special emphasis on the MOS discrete-time implementation. This implementation is demonstrated by the presentation of several circuits where the MOS parametric amplifier cell is used: small gain amplifier, comparator with embedded pre-amplification, discrete-time mixer/IIR-Filter, and analog-to-digital converter (ADC). Experimental results are shown to validate the overall design technique.

The research of unitary concepts in solid state and molecular chemistry is of current interest for both chemist and physicist communities. It is clear that due to their relative simplicity, low dimensional materials have attracted most of the attention. Thus, many non-trivial problems were solved in chain systems, giving some insight into the behavior of real systems which would otherwise be untractable. The NATO Advanced Research Workshop on "Organic and Inorganic Low-Dimensional Crystalline Materials" was organized to review the most striking electronic properties exhibited by organic and inorganic sytems whose space dimensionality ranges from zero (Od) to one (1d), and to discuss related scientific and technological potentials. The initial objectives of this Workshop were, respectively: i) To research unitary concepts in solid state physics, in particular for one dimensional compounds, ii) To reinforce, through a close coupling between theory and experiment, the interplay between organic and inorganic chemistry, on the one hand, and solid state physics on the other, iii) To get a salient understanding of new low-dimensional materials showing "exotic" physical properties, in conjunction with structural features.

This book focuses on the study of synthesized ZnO powder using Zn(CH3COO)2 2H2O precursor, methanol (as solvent), and sodium hydroxide (NaOH) to vary the pH. The successfully synthesized ZnO powder from the sol-gel centrifugation and sol-gel storage methods were characterized and investigated by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, UV visible spectroscopy, and photoluminescence test to compare the properties of the nanoparticles. The best characteristic of the ZnO powder from both methods was observed when the powders were coated on an ITO glass to fabricate a PEC. The current density voltage performances of both PECs were investigated under luminescent and dark conditions.
"

At extremely low temperatures, clouds of bosonic atoms form what is known as a Bose-Einstein condensate. Recently, it has become clear that many different types of condensates -- so called fragmented condensates -- exist. In order to tell whether fragmentation occurs or not, it is necessary to solve the full many-body Schrodinger equation, a task that remained elusive for experimentally relevant conditions for many years. In this thesis the first numerically exact solutions of the time-dependent many-body Schrodinger equation for a bosonic Josephson junction are provided and compared to the approximate Gross-Pitaevskii and Bose-Hubbard theories. It is thereby shown that the dynamics of Bose-Einstein condensates is far more intricate than one would anticipate based on these approximations. A special conceptual innovation in this thesis are optimal lattice models. It is shown how all quantum lattice models of condensed matter physics that are based on Wannier functions, e.g. the Bose/Fermi Hubbard model, can be optimized variationally. This leads to exciting new physics."

This thesis details the significant progress made in improving the performance of organic transistors and the network conductivity of carbon nanotubes. The first section investigates organic semiconductor nucleation and growth on the most common dielectric surface used to fabricate organic thin film transistors. The nucleation and growth of the semiconductor was determined to be a critical factor affecting the device performance. Excellent dielectric modification layers, which promote desirable semiconductor growth leading to high conductivity were identified, and a technologically relevant deposition technique was developed to fabricate high quality dielectric modification layers over large areas. This may represent an important step towards the realization of large area organic circuity. In the final section, lessons learned from studying organic semiconductor nucleation and growth were utilized to improve the conductivity of carbon nanotube networks. Selective nucleation of materials at the junctions between nanotubes in the network significantly decreased the network's sheet resistance. The resulting networks may be promising candidates for transparent electrodes with a variety of optoelectronic applications.

The book covers all aspects from the expansion of the Boltzmann transport equation with harmonic functions to application to devices, where transport in the bulk and in inversion layers is considered. The important aspects of stabilization and band structure mapping are discussed in detail. This is done not only for the full band structure of the 3D k-space, but also for the warped band structure of the quasi 2D hole gas. Efficient methods for building the Schrodinger equation for arbitrary surface or strain directions, gridding of the 2D k-space and solving it together with the other two equations are presented."

Density functional theory (DFT) has become the standard workhorse for quantum mechanical simulations as it offers a good compromise between accuracy and computational cost.
However, there are many important systems for which DFT performs very poorly, most notably strongly-correlated materials, resulting in a significant recent growth in interest in 'beyond DFT' methods. The widely used DFT+U technique, in particular, involves the addition of explicit Coulomb repulsion terms to reproduce the physics of spatially-localised electronic subspaces.
The magnitude of these corrective terms, measured by the famous Hubbard U parameter, has received much attention but less so for the projections used to delineate these subspaces.
The dependence on the choice of these projections is studied in detail here and a method to overcome this ambiguity in DFT+U, by self-consistently determining the projections, is introduced.
The author shows how nonorthogonal representations for electronic states may be used to construct these projections and, furthermore, how DFT+U may be implemented with a linearly increasing cost with respect to system size.
The use of nonorthogonal functions in the context of electronic structure calculations is extensively discussed and clarified, with new interpretations and results, and, on this topic, this work may serve as a reference for future workers in the field."

A modern and concise treatment of the solid state electronic devices that are fundamental to electronic systems and information technology is provided in this book. The main devices that comprise semiconductor integrated circuits are covered in a clear manner accessible to the wide range of scientific and engineering disciplines that are impacted by this technology. Catering to a wider audience is becoming increasingly important as the field of electronic materials and devices becomes more interdisciplinary, with applications in biology, chemistry and electro-mechanical devices (to name a few) becoming more prevalent. Updated and state-of-the-art advancements are included along with emerging trends in electronic devices and their applications. In addition, an appendix containing the relevant physical background will be included to assist readers from different disciplines and provide a review for those more familiar with the area. Readers of this book can expect to derive a solid foundation for understanding modern electronic devices and also be prepared for future developments and advancements in this far-reaching area of science and technology.

The book contains a summary of our knowledge of power semiconductor structures. It presents first a short historic introduction (Chap. I) as well as a brief selection of facts from solid state physics, in particular those related to power semiconductors (Chap. 2). The book deals with diode structures in Chap. 3. In addition to fundamental facts in pn-junction theory, the book covers mainly the important processes of power structures. It describes the emitter efficiency and function of microleaks (shunts). the p +p and n + n junctions, and in particular the recent theory of the pin, pvn and p1tn junctions, whose role appears to be decisive for the forward mode not only of diode structures but also of more complex ones. For power diode structures the reverse mode is the decisive factor in pn-junction breakdown theory. The presentation given here uses engineering features (the multiplication factor M and the experimentally detected laws for the volume and surface of crystals), which condenses the presentation and makes the mathematical apparatus simpler. The discussion of diode structures is complemented by data on the tunnel phenomenon as well as on the properties of the semiconductor metal contact which forms the outer layers of the diode or more complex structure. A separate chapter (Chap. 4) is devoted to the two-transistor equivalent of the four layer structure and the solution of the four-layer structure in various modes. This presentation is also directed mainly towards the power aspect and the new components."

Thin films are widely used in the electronic device industry. As the trend for miniaturization of electronic devices moves into the nanoscale domain, the reliability of thin films becomes an increasing concern. Building on the author's previous book, Electronic Thin Film Science by Tu, Mayer and Feldman, and based on a graduate course at UCLA given by the author, this new book focuses on reliability science and the processing of thin films. Early chapters address fundamental topics in thin film processes and reliability, including deposition, surface energy and atomic diffusion, before moving onto systematically explain irreversible processes in interconnect and packaging technologies. Describing electromigration, thermomigration and stress migration, with a closing chapter dedicated to failure analysis, the reader will come away with a complete theoretical and practical understanding of electronic thin film reliability. Kept mathematically simple, with real-world examples, this book is ideal for graduate students, researchers and practitioners.

This book contains rewiev articles presenting the current status of high-temperature superconductivity research. The articles cover synthesis issues, materials properties and most fundamental theoretical problems. Applications of high- temperature superconductors are also reflected in several contributions.
The book addresses researchers working in fundamental research in solid-state physics as well as engineers developing new materials for industrial applications.

This Volume 44 of Advances in Solid State Physics contains the written versions of most of the invited lectures of the Spring Meeting of the Condensed Matter Physics section of the Deutsche Physikalische Gesellschaft held from March 8 to 12, 2004 in Regensburg, Germany. Many of the topical talks given at the numerous and very lively symposia are also included. They have covered extremely interesting and timely subjects. Thus the book truly reflects the status of the field of solid state physics in 2004, and indicates its importance, not only in Germany but also internationally.

The Aharonov-Bohm effect is associated with cyclic motion. It is one of a number of anholonomic effects, and this means that the dynamical description depends on the current position of the system and on the path by which it reached that position.
An example of an anholonomic effect is Foucault's famous pendulum, which simply demonstrates the Earth's rotation. The Sagnac effect - a light beam passing around a rotated system of mirrors - is another example. Modern dynamical developments such as Hannay's angle and Berry's phase are further useful examples.

Starting from the early experiments, this detailed presentation, containing more than 500 references, provides a comprehensive review on current-induced nonequilibrium phenomena in quasi-one-dimensional superconductors, leading the reader from the fundamentals to the most recent research results. Experiments on monocrystalline filaments (whiskers) - including those obtained by the author - are compared with results on long thin film microbridges and related species and interpreted within the theoretical framework. Instructions on experimental techniques are given and yet unresolved problems are discussed. The book is well suited as an introduction for the novice and as a handbook for the active researcher.

From semiconductor fundamentals to semiconductor devices used in the telecommunications and computing industries, this 2005 book provides a solid grounding in the most important devices used in the hottest areas of electronic engineering. The book includes coverage of future approaches to computing hardware and RF power amplifiers, and explains how emerging trends and system demands of computing and telecommunications systems influence the choice, design and operation of semiconductors. Next, the field effect devices are described, including MODFETs and MOSFETs. Short channel effects and the challenges faced by continuing miniaturisation are then addressed. The rest of the book discusses the structure, behaviour, and operating requirements of semiconductor devices used in lightwave and wireless telecommunications systems. This is both an excellent senior/graduate text, and a valuable reference for engineers and researchers in the field.