Amorphous Solids


Book Description

It is now ten years since it was first convincingly shown that below 1 K the ther mal conductivity and the heat capacity of amorphous solids behave in a way which is strikingly different to that of crystalline solids. Since that time there has been a wide variety of experimental and theoretical studies which have not only defined and clarified the low temperature problem more closely, but have also linked these differences between amorphous and crystalline solids to those suggested by older acoustic and thermal experiments (extending up to 100 K). The interest in this somewhat restricted branch of physics lies to a considerable extent in the fact that the differences were so unexpected. It might be thought that as the tempera ture, probing frequency, or more generally the energy decreases, a continuum de scription in which structural differences between glass and crystal are concealed should become more accurate. In a sense this is true, but it appears that there exists in an amorphous solid a large density of additional excitations which have no counterpart in normal crystals. This book presents a survey of the wide range of experimental investigations of these low energy excitations, together with a re view of the various theoretical models put forward to explain their existence and nature.




Physical Properties of Amorphous Materials


Book Description

The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.




Optical Properties of Crystalline and Amorphous Semiconductors


Book Description

Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Principles presents an introduction to the fundamental optical properties of semiconductors. This book presents tutorial articles in the categories of materials and fundamental principles (Chapter 1), optical properties in the reststrahlen region (Chapter 2), those in the interband transition region (Chapters 3 and 4) and at or below the fundamental absorption edge (Chapter 5). Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Principles is presented in a form which could serve to teach the underlying concepts of semiconductor optical properties and their implementation. This book is an invaluable resource for device engineers, solid-state physicists, material scientists and students specializing in the fields of semiconductor physics and device engineering.




Properties and Applications of Amorphous Materials


Book Description

The aim of this NATO ASI has been to present an up-to-date overview of current areas of interest in amorphous materials, with particular emphasis on electronic properties and device applications. In order to limit the material to a manageable amount, the meeting was concerned almost exclusively with semiconducting materials. This volume should be regarded as a follow-on to the NATO ASI held in Sozopol, Bulgaria in 1996 and published as "Amorphous Insulators and Semiconductors" edited by M.F. Thorpe and M.1. Mitkova (Kluwer Academic Publishers, NATO ASI series, 3 High Technology - Vol. 23). The lectures and seminars fill the gap between graduate courses and research seminars. The lecturers and seminar speakers were chosen as experts in their respective areas, and the lectures and seminars that were given are presented in this volume. During the first week of the meeting, an emphasis was placed on introductory lectures while the second week focused more on research seminars. There were two very good poster sessions that generated a lot of discussion, but these are not reproduced in this volume as the editors wanted to have only larger contributions to make the proceedings more coherent.




Scientific and Technical Aerospace Reports


Book Description

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.







Advances in Amorphous Semiconductors


Book Description

Amorphous materials differ significantly from their crystalline counterparts in several ways that create unique issues in their use. This book explores these issues and their implications, and provides a full treatment of both experimental and theoretical studies in the field. Advances in Amorphous Semiconductors covers a wide range of studies on hydrogenated amorphous silicon, amorphous chalcogenides, and some oxide glasses. It reviews structural properties, properties associated with the charge carrier-phonon interaction, defects, electronic transport, photoconductivity, and some applications of amorphous semiconductors. The book explains a number of recent advances in semiconductor research, including some of the editors' own findings. It addresses some of the problems associated with the validity of the effective mass approximation, whether K is a good quantum number, and the concepts of phonons and excitons. It also discusses recent progress made in understanding light-induced degradations in amorphous semiconductors, which is seen as the most limiting problem in device applications. The book presents a comprehensive review of both experimental and theoretical studies on amorphous semiconductors, which will be useful to students, researchers, and instructors in the field of amorphous solids.




Physics of Amorphous Semiconductors


Book Description

This is a useful textbook for graduate students in the fields of solid state physics and chemistry as well as electronic engineering. Presenting the fundamentals of amorphous semiconductors clearly, it will be essential reading for young scientists intending to develop new preparation techniques for more ideal amorphous semiconductors e.g. a-Si: H, to fabricate stable and efficient solar cells and thin film transistors and new artificial amorphous materials such as multilayers for quantum devices.A large portion is devoted to the latest developments of amorphous semiconductors including electronic properties of a-Si: H, nature of weak bonds and gap states in a-Si: H, mechanisms for light-induced defect creation in a-Si: H and chalcogenides, quantum phenomena in multilayer fi




Amorphous Solids


Book Description

It is now ten years since it was first convincingly shown that below 1 K the ther mal conductivity and the heat capacity of amorphous solids behave in a way which is strikingly different to that of crystalline solids. Since that time there has been a wide variety of experimental and theoretical studies which have not only defined and clarified the low temperature problem more closely, but have also linked these differences between amorphous and crystalline solids to those suggested by older acoustic and thermal experiments (extending up to 100 K). The interest in this somewhat restricted branch of physics lies to a considerable extent in the fact that the differences were so unexpected. It might be thought that as the tempera ture, probing frequency, or more generally the energy decreases, a continuum de scription in which structural differences between glass and crystal are concealed should become more accurate. In a sense this is true, but it appears that there exists in an amorphous solid a large density of additional excitations which have no counterpart in normal crystals. This book presents a survey of the wide range of experimental investigations of these low energy excitations, together with a re view of the various theoretical models put forward to explain their existence and nature.