A review summarising the current state of research in the field, bridging the gaps in the existing literature. All the chapters are written by world leaders in research and development and guide readers through the details of photo-induced metastability and the results of the latest experiments and simulations not found in standard monographs on this topic. A useful reference not only for graduates but also for scientific and industrial researchers. With a foreword of Kazunobu Tanaka

Understanding the structural unit of crystalline solids is vital in determining their optical and electronic properties. However, the disordered nature of amorphous semiconductors, where no long-range order is retained, makes it difficult to determine their structure using traditional methods. This book shows how computer modelling can be used to overcome the difficulties that arise in the atomic scale identification of amorphous semiconductors. The book explains how to generate a random structure using computer modelling, providing readers with the techniques to construct realistic material structures. It shows how the optical and electronic properties are related to random structures. Readers will be able to understand the characteristic features of disordered semiconductors. The structural and electronic modifications by photon irradiation are also discussed in detail. This book is ideal for both physicists and engineers working in solid state physics, semiconductor engineering and electrical engineering.

Amorphous semiconductors are subtances in the amorphous solid state that have the properties of a semiconductor and which are either covalent or tetrahedrally bonded amorphous semiconductors or chelcogenide glasses. Developed from both a theoretical and experimental viewpoint Deals with, amongst others, preparation techniques, structural, optical and electronic properties, and light induced phenomena Explores different types of amorphous semiconductors including amorphous silicon, amorphous semiconducting oxides and chalcogenide glasses Applications include solar cells, thin film transistors, sensors, optical memory devices and flat screen devices including televisions

Semiconductors are at the heart of modern living. Almost everything we do, be it work, travel, communication, or entertainment, all depend on some feature of semiconductor technology. Comprehensive Semiconductor Science and Technology, Six Volume Set captures the breadth of this important field, and presents it in a single source to the large audience who study, make, and exploit semiconductors. Previous attempts at this achievement have been abbreviated, and have omitted important topics. Written and Edited by a truly international team of experts, this work delivers an objective yet cohesive global review of the semiconductor world. The work is divided into three sections. The first section is concerned with the fundamental physics of semiconductors, showing how the electronic features and the lattice dynamics change drastically when systems vary from bulk to a low-dimensional structure and further to a nanometer size. Throughout this section there is an emphasis on the full understanding of the underlying physics. The second section deals largely with the transformation of the conceptual framework of solid state physics into devices and systems which require the growth of extremely high purity, nearly defect-free bulk and epitaxial materials. The last section is devoted to exploitation of the knowledge described in the previous sections to highlight the spectrum of devices we see all around us. Provides a comprehensive global picture of the semiconductor world Each of the work's three sections presents a complete description of one aspect of the whole Written and Edited by a truly international team of experts

This book provides introductory, comprehensive, and concise descriptions of amorphous chalcogenide semiconductors and related materials. It includes comparative portraits of the chalcogenide and related materials including amorphous hydrogenated Si, oxide and halide glasses, and organic polymers. It also describes effects of non-equilibrium disorder, in comparison with those in crystalline semiconductors.

Despite the large number of successful commercial applications of chalcogenide glasses (ChGs) ranging from memory devices to photonics and medical imaging detectors, the understanding of a fundamental property - photo-induced structural metastability is not yet complete. The inherent trend of amorphous chalcogenides to convert to its crystalline counterpart, can on the one hand, be directly utilized in phase-change memories, while on the other hand can degrade glass properties for applications in sensing. Furthermore, because the structure of amorphous semiconductors is not fixed by thermodynamic equilibrium conditions, its transformation can be triggered by optical/X-ray excitation and influenced by thermal heating or applied electric field. Each case has its own peculiarities of transformation. Thus, to ensure effective application of a given ChG, a solid understanding of the causes for the structural transformation on the microscopic level has to be developed. This thesis is devoted to the study of photo-induced metastability of the most widely used ChG - amorphous selenium (a-Se), and archetypal a-GexSe100-x glass compounds relevant for applications in sensing. We focus on the research of defect creation and defect relaxation processes in these materials since it is hypothesized to be the root cause for structural transformations affecting stability. The detailed experimental and theoretical study is carried out to reveal the pathways from a micro-level, i.e. defect creation/relaxation, to the macro-level photo-induced effects formation, namely photodarkening (PD), photobleaching (PB) and photo-induced crystallization (PC) and their kinetics. The effects of temperature and energy of excitation on PD kinetics are studied in a- Se. Distinctly different PD effects are observed in the case of sub-bandgap and above- bandgap excitation. It is found that above-bandgap excitation causes only transient photodarkening with a temperature independent relaxation time and no significant structural rearrangements. In contrast, sub-bandgap excitation causes both transient and metastable PD effects. Whereas the mechanism responsible for transient PD for sub- bandgap excitation is analogous to that in the case of above-bandgap excitation, metastable PD is controlled by the formation of self-trapped excitons resulting in structural transformations into configuration defects. Subsequent relaxation in the latter case is shown to be a thermally activated process at elevated temperatures; or configuration tunneling below the room temperature. It is confirmed that if left unrestored, metastable PD acts as a precursor for photo-induced crystallization. Detailed investigation of the effects of different substrates and temperature on photo- induced crystallization in a-Se demonstrates that the onset of PC is suppressed by softening of the film-substrate interface and/or by operating at temperatures near the glass transition. Further, photodarkening and photobleaching effects are investigated in a-GexSe100-x as a function of composition across the glass forming region. The Ge:Se ratio is found to play a decisive role in the observed effects. The critical concentration of Ge ≈30% is highlighted to correspond to the crossover from transient PB to a mixture of transient PD and metastable PB. The underlying microscopic mechanism is governed by the availability of lone pair (LP) states at Se atoms. For low-Ge content films (x

This book covers electronic and structural properties of light-induced defects, light-induced defect creation processes, and related phenomena in crystalline, amorphous, and microcrystalline semiconductors. It provides a theoretical treatment of recombination-enhanced defect reaction in crystalline semiconductors, particularly GaAs and related mate