This thesis examines the unique properties of gallium arsenide (GaAs)-based quantum-dot semiconductor optical amplifiers for optical communication networks, introducing readers to their fundamentals, basic parameters and manifold applications. The static and dynamic properties of these amplifiers are discussed extensively in comparison to conventional, non quantum-dot based amplifiers, and their unique advantages are elaborated on, such as the fast carrier dynamics and the decoupling of gain and phase dynamics. In addition to diverse amplification scenarios involving single and multiple high symbol rate amplitude and phase-coded data signals, wide-range wavelength conversion as a key functionality for optical signal processing is investigated and discussed in detail. Furthermore, two novel device concepts are developed and demonstrated that have the potential to significantly simplify network architectures, reducing the investment and maintenance costs as well as the energy consumption of future networks.

This work studies the magnetic behavior of ZnO nanoparticles capped with different organic molecules and showing room-temperature ferromagnetism (RTFM). Of particular significance is the combination of element-specific X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) techniques, which demonstrates the intrinsic occurrence of RTFM in these systems and indicates that it is not related to the 3-D states of the metallic cation but is relayed along the conduction band of the semiconductor. The discovery of room-temperature ferromagnetism (RTFM) in semiconductors holds great promise in future spintronics technologies. Further results presented here include O K-edge XMCD studies, which demonstrate that the oxygen ions have a ferromagnetic response in these ZnO-based systems, providing the first direct support for claims regarding the appearance of oxygen ferromagnetism in oxide semiconductors at the nanoscale.

Three dimensional (3D) optical geometries are becoming more common in the literature and lexicon of solar cells. "Three Dimensional Solar Cells Based on Optical Confinement Geometries" describes and reveals the basic operational nuances of 3D photovoltaics using three standard tools: Equivalent Circuit Models, Ray Tracing Optics in the Cavity, and Absorber Spectral Response. These tools aide in understanding experimental absorption profile and device parameters including Jsc, Voc, Fill Factor, and EQE. These methods also apply to individual optical confinement geometry device, integrated optical confinement geometry device, and hybrid optical confinement geometry device.
Additionally, this book discusses the importance of these methods in achieving the goal of high efficiency solar cells and suggests a possible application in large-scale photovoltaics business, like solar farms.

A comprehensive device model considering both spatial distributions of the terahertz field and the field-effect self-mixing factor has been constructed for the first time in the thesis. The author has found that it is the strongly localized terahertz field induced in a small fraction of the gated electron channel that plays an important role in the high responsivity. An AlGaN/GaN-based high-electron-mobility transistor with a 2-micron-sized gate and integrated dipole antennas has been developed and can offer a noise-equivalent power as low as 40 pW/Hz1/2 at 900 GHz. By further reducing the gate length down to 0.2 micron, a noise-equivalent power of 6 pW/Hz1/2 has been achieved. This thesis provides detailed experimental techniques and device simulation for revealing the self-mixing mechanism including a scanning probe technique for evaluating the effectiveness of terahertz antennas. As such, the thesis could be served as a valuable introduction towards further development of high-sensitivity field-effect terahertz detectors for practical applications.

An important resource for students, engineers and researchers working in the area of thin film deposition using "physical vapor deposition" (e.g. "sputtering") for semiconductor, liquid crystal displays, high density recording media and photovoltaic device (e.g. thin film solar cell) manufacturing. This book also reviews microelectronics industry topics such as history of inventions and technology trends, recent developments in sputtering technologies, manufacturing steps that require sputtering of thin films, the properties of thin films and the role of sputtering target performance on overall productivity of various processes. Two unique chapters of this book deal with productivity and troubleshooting issues.

The content of the book has been divided into two sections: (a) the "first section" (Chapter 1 to Chapter 3) has been prepared for the readers from a range of disciplines (e.g. electrical, chemical, chemistry, physics) trying to get an insight into use of sputtered films in various devices (e.g. semiconductor, display, photovoltaic, data storage), basic of sputtering and performance of sputtering target in relation to productivity, and (b) the "second section" (Chapter 4 to Chapter 8) has been prepared for readers who already have background knowledge of sputter deposition of thin films, materials science principles and interested in the details of sputtering target manufacturing methods, sputtering behavior and thin film properties specific to semiconductor, liquid crystal display, photovoltaic and magnetic data storage applications.

In Chapters 5 to 8, a general structure has been used, i.e. a description of the applications of sputtered thin films, sputtering target manufacturing methods (including flow charts), sputtering behavior of targets (e.g. current - voltage relationship, deposition rate) and thin film properties (e.g. microstructure, stresses, electrical properties, in-film particles). While discussing these topics, attempts have been made to include examples from the actual commercial processes to highlight the increased complexity of the commercial processes with the growth of advanced technologies. In addition to personnel working in industry setting, university researchers with advanced knowledge of sputtering would also find discussion of such topics (e.g. attributes of target design, chamber design, target microstructure, sputter surface characteristics, various troubleshooting issues) useful.

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Unique coverage of sputtering target manufacturing methods in the light of semiconductor, displays, data storage and photovoltaic industry requirementsPractical information on technology trends, role of sputtering and major OEMs Discussion on properties of a wide variety of thin films which include silicides, conductors, diffusion barriers, transparent conducting oxides, magnetic films etc.Practical case-studies on target performance and troubleshootingEssential technological information for students, engineers and scientists working in the semiconductor, display, data storage and photovoltaic industry

This book is a comprehensive guide to both the fundamentals of thermal sensors and their advanced functions. Key topics include sensor materials, CMOS-compatible sensors, measurement capabilities, thermal management and manufacturing processes. The introductory chapter covers the basic principles of thermal sensors from the essentials of heat transfer to smart wireless sensors. Later chapters illustrate the wide range of thermal sensor uses, from microprocessor thermal sensing to energy converter applications. Modeling and simulation techniques are used to explain the future direction of the field. Designed for researchers and practitioners working with wireless sensors and thermal management, Thermal Sensors: Principles and Applications for Semiconductor Industries is a valuable reference to the benefits and challenges these sensors offer. Advanced-level students studying mechanical or electrical engineering and networks will also find the content useful.

This thesis combines highly accurate optical spectroscopy data on the recently discovered iron-based high-temperature superconductors with an incisive theoretical analysis. Three outstanding results are reported: (1) The superconductivity-induced modification of the far-infrared conductivity of an iron arsenide with minimal chemical disorder is quantitatively described by means of a strong-coupling theory for spin fluctuation mediated Cooper pairing. The formalism developed in this thesis also describes prior spectroscopic data on more disordered compounds. (2) The same materials exhibit a sharp superconductivity-induced anomaly for photon energies around 2.5 eV, two orders of magnitude larger than the superconducting energy gap. The author provides a qualitative interpretation of this unprecedented observation, which is based on the multiband nature of the superconducting state. (3) The thesis also develops a comprehensive description of a superconducting, yet optically transparent iron chalcogenide compound. The author shows that this highly unusual behavior can be explained as a result of the nanoscopic coexistence of insulating and superconducting phases, and he uses a combination of two complementary experimental methods - scanning near-field optical microscopy and low-energy muon spin rotation - to directly image the phase coexistence and quantitatively determine the phase composition. These data have important implications for the interpretation of data from other experimental probes.

This revised and updated edition of the well-received book by C. Klingshirn provides an introduction to and an overview of all aspects of semiconductor optics, from IR to visible and UV. It has been split into two volumes and rearranged to offer a clearer structure of the course content. Inserts on important experimental techniques as well as sections on topical research have been added to support research-oriented teaching and learning. Volume 1 provides an introduction to the linear optical properties of semiconductors. The mathematical treatment has been kept as elementary as possible to allow an intuitive approach to the understanding of results of semiconductor spectroscopy. Building on the phenomenological model of the Lorentz oscillator, the book describes the interaction of light with fundamental optical excitations in semiconductors (phonons, free carriers, excitons). It also offers a broad review of seminal research results augmented by concise descriptions of the relevant experimental techniques, e.g., Fourier transform IR spectroscopy, ellipsometry, modulation spectroscopy and spatially resolved methods, to name a few. Further, it picks up on hot topics in current research, like quantum structures, mono-layer semiconductors or Perovskites. The experimental aspects of semiconductor optics are complemented by an in-depth discussion of group theory in solid-state optics. Covering subjects ranging from physics to materials science and optoelectronics, this book provides a lively and comprehensive introduction to semiconductor optics. With over 120 problems, more than 480 figures, abstracts to each chapter, as well as boxed inserts and a detailed index, it is intended for use in graduate courses in physics and neighboring sciences like material science and electrical engineering. It is also a valuable reference resource for doctoral and advanced researchers.

This thesis sheds important new light on the puzzling properties of Strontium Ruthenate. Using a sophisticated weak-coupling approach, exact within certain limits, it shows that proper treatment of spin-orbit and multi-band effects is crucial to the physics. Based on the results of these calculations, it resolves a crucial, long-standing puzzle in the field: It demonstrates why the experimentally observed time-reversal breaking is not incompatible with the observed lack of measurable edge currents. Lastly, the thesis makes predictions for the properties of the material under uniaxial strain, which are in good agreement with recent experiments -resolving the mystery of the so-called 3K phase, and suggesting the intriguing possibility that under strain the superconductor may become conventional.

Metamaterials, artificial electromagnetic media achieved by structuring on the subwave-length-scale were initially suggested for the negative index and superlensing. They became a paradigm for engineering electromagnetic space and controlling propagation of waves. The research agenda is now shifting on achieving tuneable, switchable, nonlinear and sensing functionalities. The time has come to talk about the emerging research field of metadevices employing active and tunable metamaterials with unique functionalities achieved by structuring of functional matter on the subwave-length scale. This book presents the first systematic and comprehensive summary of the reviews written by the pioneers and top-class experts in the field of metamaterials. It addresses many grand challenges of the cutting edge research for creating smaller and more efficient photonic structures and devices.

This thesis addresses the intriguing topic of the quantum tunnelling of many-body systems such as Bose-Einstein condensates. Despite the enormous amount of work on the tunneling of a single particle through a barrier, we know very little about how a system made of several or of many particles tunnels through a barrier to open space. The present work uses numerically exact solutions of the time-dependent many-boson Schroedinger equation to explore the rich physics of the tunneling to open space process in ultracold bosonic particles that are initially prepared as a Bose-Einstein condensate and subsequently allowed to tunnel through a barrier to open space. The many-body process is built up from concurrently occurring single particle processes that are characterized by different momenta. These momenta correspond to the chemical potentials of systems with decreasing particle number. The many-boson process exhibits exciting collective phenomena: the escaping particles fragment and lose their coherence with the source and among each other, whilst correlations build up within the system. The detailed understanding of the many-body process is used to devise and test a scheme to control the final state, momentum distributions and even the correlation dynamics of the tunneling process.

In this thesis the author presents the results of extensive spectroscopy experiments beyond the bounds of each transition element to clarify the origins of characteristic spectral features and charge dynamics in charge-spin-orbital coupled phenomena in Mott-transition oxides. Several counterpart 3d transition-metal oxides were adopted as model systems suitable for examining the mechanisms involved, and their electronic structures were systematically investigated using three main spectroscopy methods.

Comparative studies on the charge dynamics and Mott transition features of transition-metal oxides were performed: Charge dynamics and thermoelectricity in a typical Mott transition system La1 xSrxVO3, charge dynamics in a doped valence-bond solid system (Ti1 xVx)2O3 and in layered nickelates R2-xSrxNiO4 with charge-ordering instability are investigated thoroughly. The results obtained successfully provide a number of novel insights into the emergent phenomena near the Mott transition.

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In this thesis, the author investigates hidden-order phase transition at" T"0 = 17.5 K in the heavy-fermion URu2Si2. The four-fold rotational symmetry breaking in the hidden order phase, which imposes a strong constraint on the theoretical model, is observed through the magnetic torque measurement. The translationally invariant phase with broken rotational symmetry is interpreted as meaning that the hidden-order phase is an electronic "nematic" phase. The observation of such nematicity in URu2Si2 indicates a ubiquitous nature among the strongly correlated electron systems.

The author also studies the superconducting state of URu2Si2 below" T"c = 1.4 K, which coexists with the hidden-order phase. A peculiar vortex penetration in the superconducting state is found, which may be related to the rotational symmetry breaking in the hidden-order phase. The author also identifies a vortex lattice melting transition. This transport study provides essential clues to the underlying issue of quasiparticle dynamics as to whether a quasiparticle Bloch state is realized in the periodic vortex lattice.

This thesis deals with topological orders from two different perspectives: from a condensed matter point of view, where topological orders are considered as breakthrough phases of matter; and from the emerging realm of quantum computation, where topological quantum codes are considered the most appealing platform against decoherence. The thesis reports remarkable studies from both sides. It thoroughly investigates a topological order called the double semion model, a counterpart of the Kitaev model but exhibiting richer quasiparticles as excitations. A new model for symmetry enriched topological order is constructed, which adds an onsite global symmetry to the double semion model. Using this topological phase, a new example of topological code is developed, the semion code, which is non-CSS, additive, non-Pauli and within the stabiliser formalism. Furthermore, the thesis analyses the Rashba spin-orbit coupling within topological insulators, turning the helical edge states into generic edges modes with potential application in spinstronics. New types of topological superconductors are proposed and the novel properties of the correspondingly created Majorana fermions are investigated. These Majorana fermions have inherent properties enabling braiding and the performance of logical gates as fundamental blocks for a universsal quantum computator.

"Semiconductors and Semimetals" has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the "Willardson and Beer" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in "Semiconductors and Semimetals" have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scientific laboratories and modern industry.
Written and edited by internationally renowned experts
Relevant to a wide readership: physicists, chemists, materials scientists, and device engineers in academia, scientific laboratories and modern industry

This monograph provides an introductory discussion of evanescent waves and plasmons, describes their properties and uses, and shows how they are fundamental when operating with nanoscale optics. Far field optics is not suitable for the design, description, and operation of devices at this nanometre scale. Instead one must work with models based on near-field optics and surface evanescent waves. The new discipline of plasmonics has grown to encompass the generation and application of plasmons both as a travelling excitation in a nanostructure and as a stationary enhancement of the electrical field near metal nanosurfaces. The book begins with a brief review of the basic concepts of electromagnetism, then introduces evanescent waves through reflection and refraction, and shows how they appear in diffraction problems, before discussing the role that they play in optical waveguides and sensors. The application of evanescent waves in super-resolution devices is briefly presented, before plasmons are introduced. The surface plasmon polaritons (SPPs) are then treated, highlighting their potential applications also in ultra-compact circuitry. The book concludes with a discussion of the quantization of evanescent waves and quantum information processing. The book is intended for students and researchers who wish to enter the field or to have some insight into the matter. It is not a textbook but simply an introduction to more complete and in-depth discussions. The field of plasmonics has exploded in the last ten years, and most of the material treated in this book is scattered in original or review papers. A short comprehensive treatment is missing; this book is intended to provide just that.

This multi-contributor handbook discusses Molecular Beam Epitaxy (MBE), an epitaxial deposition technique which involves laying down layers of materials with atomic thicknesses on to substrates. It summarizes MBE research and application in epitaxial growth with close discussion and a how to on processing molecular or atomic beams that occur on a surface of a heated crystalline substrate in a vacuum.

MBE has expanded in importance over the past thirty years (in terms of unique authors, papers and conferences) from a pure research domain into commercial applications (prototype device structures and more at the advanced research stage). MBE is important because it enables new device phenomena and facilitates the production of multiple layered structures with extremely fine dimensional and compositional control. The techniques can be deployed wherever precise thin-film devices with enhanced and unique properties for computing, optics or photonics are required. This book covers the advances made by MBE both in research and mass production of electronic and optoelectronic devices. It includes new semiconductor materials, new device structures which are commercially available, and many more which are at the advanced research stage.
Condenses fundamental science of MBE into a modern reference, speeding up literature reviewDiscusses new materials, novel applications and new device structures, groundingcurrent commercial applications with modern understanding in industry and research Coverage of MBE as mass production epitaxial technology enhances processing efficiency and throughput for semiconductor industry and nanostructured semiconductor materials research community"

Characterization of Semiconductor Heterostructures and Nanostructures is structured so that each chapter is devoted to a specific characterization technique used in the understanding of the properties (structural, physical, chemical, electrical etc..) of semiconductor quantum wells and superlattices. An additionalchapter is devoted toab initio modeling.

The book has two basic aims. The first is educational, providing the basic concepts of each of the selected techniques with an approach understandable by advanced students in Physics, Chemistry, Material Science, Engineering, Nanotechnology. The second aim is to provide a selected set of examples from the recent literature of the TOP results obtained with the specific technique in understanding the properties of semiconductor heterostructures and nanostructures. Each chapter has this double structure: the first part devoted to explain the basic concepts, and the second to the discussion of the most peculiar and innovative examples.

The topic of quantum wells, wires and dots should be seen as a pretext of applying top level characterization techniques in understanding the structural, electronic etc properties of matter at the nanometer (and even sub-nanometer) scale. In this respect it is an essentialreferencein the much broader, and extremely hot, field of Nanotechnology.
- Comprehensive collection of the most powerful characterization techniques for semiconductors heterostructures and nanostructures.
- Most of the chapters are authored by scientists that are world wide among the top-ten in publication ranking of the specific field.
- Each chapter starts with a didactic introduction on the technique.
- The second part of each chapters deals with a selection of top examples highlighting the power of the specific technique to analyse the properties of semiconductors heterostructures and nanostructures."

This book presents the proceedings of the 2nd Karl Schwarzschild Meeting on Gravitational Physics, focused on the general theme of black holes, gravity and information.Specialists in the field of black hole physics and rising young researchers present the latest findings on the broad topic of black holes, gravity, and information, highlighting its applications to astrophysics, cosmology, particle physics, and strongly correlated systems.

In this book the author presents two important findings revealed by high-precision magnetic penetration depth measurements in iron-based superconductors which exhibit high-transition temperature superconductivity up to 55 K: one is the fact that the superconducting gap structure in iron-based superconductors depends on a detailed electronic structure of individual materials, and the other is the first strong evidence for the presence of a quantum critical point (QCP) beneath the superconducting dome of iron-based superconductors. The magnetic penetration depth is a powerful probe to elucidate the superconducting gap structure which is intimately related to the pairing mechanism of superconductivity. The author discusses the possible gap structure of individual iron-based superconductors by comparing the gap structure obtained from the penetration depth measurements with theoretical predictions, indicating that the non-universal superconducting gap structure in iron-pnictides can be interpreted in the framework of A1g symmetry. This result imposes a strong constraint on the pairing mechanism of iron-based superconductors. The author also shows clear evidence for the quantum criticality inside the superconducting dome from the absolute zero-temperature penetration depth measurements as a function of chemical composition. A sharp peak of the penetration depth at a certain composition demonstrates pronounced quantum fluctuations associated with the QCP, which separates two distinct superconducting phases. This gives the first convincing signature of a second-order quantum phase transition deep inside the superconducting dome, which may address a key question on the general phase diagram of unconventional superconductivity in the vicinity of a QCP.

Ge and III-V compounds, semiconductors with high carrier mobilities, are candidates to replace Si as the channel in MOS devices. 2D materials - like graphene and MoS_2 - are also envisioned to replace Si in the future. This thesis is devoted to the first-principles modeling of the vibrational properties of these novel channel materials. The first part of the thesis focuses on the vibrational properties of various oxides on Ge, making it possible to identify the vibrational signature of specific defects which could hamper the proper functioning of MOSFETs. The second part of the thesis reports on the electronic and vibrational properties of novel 2D materials like silicene and germanene, the Si and Ge 2D counterparts of graphene. The interaction of these 2D materials with metallic and non-metallic substrates is investigated. It was predicted, for the first time, and later experimentally confirmed, that silicene could be grown on a non-metallic template like MoS_2, a breakthrough that could open the door to the possible use of silicene in future nanoelectronic devices.

This thesis deals with the dynamics of state-of-the-art nanophotonic semiconductor structures, providing essential information on fundamental aspects of nonlinear dynamical systems on the one hand, and technological applications in modern telecommunication on the other. Three different complex laser structures are considered in detail: (i) a quantum-dot-based semiconductor laser under optical injection from a master laser, (ii) a quantum-dot laser with optical feedback from an external resonator, and (iii) a passively mode-locked quantum-well semiconductor laser with saturable absorber under optical feedback from an external resonator. Using a broad spectrum of methods, both numerical and analytical, this work achieves new fundamental insights into the interplay of microscopically based nonlinear laser dynamics and optical perturbations by delayed feedback and injection.

This resource provides engineers with a comprehensive treatment of silicon-germanium heterojunction bipolar transistors (SiGe HBT), a semi-conductor technology that is expected to revolutionise the communications industry by offering low-cost, high-speed solutions for emerging communications needs. It offers practitioners and students a from-the-ground-up understanding of SiGe HBT devices and technology from a very broad perspective. The text covers motivation, history, materials, fabrication, device physics, operational principles, and circuit-level properties associated with SiGe. This reference explains how to design, simulate, fabricate and measure a SiGe HBT, and offers an understanding of the optimization issues and design tradeoffs of SiGe HBTs and RF/microwave circuits built with this new technology.

This thesis demonstrates that layered heterostructures of two-dimensional crystals graphene, hexagonal boron nitride, and transition metal dichalcogenides provide new and interesting interlayer transport phenomena. Low-energy electron microscopy is employed to study the surface of atomically thin WSe2 prepared by metal-organic chemical vapor deposition on epitaxial graphene substrates, and a method for unambiguously measuring the number of atomic layers is presented. Using very low-energy electrons to probe the surface of similar heterostructures, a relationship between extracted work function differences from the layers and the nature of the electrical contact between them is revealed. An extension of this analysis is applied to surface studies of MoSe2 prepared by molecular beam epitaxy on epitaxial graphene. A large work function difference is measured between the MoSe2 and graphene, and a model is provided which suggests that this observation results from an exceptional defect density in the MoSe2 film. The thesis expounds a theory for computing tunneling currents between two-dimensional crystals separated by a thin insulating barrier; a few situations resulting in resonant tunneling and negative differential resistance are illustrated by computed examples, as well as observed characteristics, for monolayer and bilayer graphene tunneling junctions and transistors.

This book addresses a wide range of topics relating to the properties and behavior of condensed matter under extreme conditions such as intense magnetic and electric fields, high pressures, heat and cold, and mechanical stresses. It is divided into four sections devoted to condensed matter theory, molecular chemistry, theoretical physics, and the philosophy and history of science. The main themes include electronic correlations in material systems under extreme pressure and temperature conditions, surface physics, the transport properties of low-dimensional electronic systems, applications of the density functional theory in molecular systems, and graphene. The book is the outcome of a workshop held at the University of Catania, Italy, in honor of Professor Renato Pucci on the occasion of his 70th birthday. It includes selected invited contributions from collaborators and co-authors of Professor Pucci during his long and successful career, as well as from other distinguished guest authors.