This book examines the potential application of semiconductor materials for gas sensor production on the basis of their fundamental, theoretical, and experimental studies. Some of these materials or their composites were applied for semiconductor gas sensor production for the first time. Special attention is paid to the model materials A2B6, which are used in the form of films with biographic surface as well as with the surface doped by donor (In, Cd, Sn, Pt, Pd etc.) and acceptor (Se and others) particles. Results of application of metal-oxide materials as adsorptionally sensitive elements are also represented in this book. These elements were produced and tested in the form of simple oxides (as SnO2, In2O3, for example) as well as in the form of composite oxide metal complexes (SnWO4, ZnO:In2O3 etc.). The book examines in detail the influence of doping on different materials and their adsorption sensitivity, persistence, selectivity, dynamic and kinetic characteristics, and other parameters. Results of thorough studies of degradation of semiconductor sensor material characteristics, when in working gas atmospheres, are represented in a special section of the book. Adsorptionally sensitive parameters of amorphous silicon, micro-, macro- and nanoporous silicon are examined and results of Si structure testing as gas sensors are also discussed in this book.

The subject of the proposed publication is to study electronic processes in a nonideal heterojunction in order to use this material in a high-quality optical fashion and for X-ray image sensor development. The effects of accumulation and erasure of recorded optical information, as well as a satisfactory consistent theory of phenomena and effects are fully described and discussed in this book. The academic level of this book is advanced: It is for specialists studying photoelectronics, the physics of surfaces and sensorics as well as university professors, lecturers and higher school teachers. It could be used also as a textbook for post-graduate students, Masters of Sciences and undergraduates. This contribution describes properties, characteristics and formation processes for nonideal heterojunction structures based on micro- and nano-crystalline thin-film semiconductors applied for optical sensors. The experimental studies concerning the nature of the conductivity features of the nonideal heterojunctions are described in detail. A new model of tunnel-hopping transport over local centers in the space-charge region of heterojunctions with a continuously changing barrier potential is developed and experimentally tested. The characteristic density and morphology of defects at the boundary and in the space charge region of a nonideal heterojunction are calculated. A comprehensive model for the recombination of carriers moving along localized states at the recombination centers of the heteroborder is created. For the first time, the nature of the photosensitivity features of the nonideal heterojunction, associated with the presence of deep centers in the space charge region and their charge exchange under conditions of photoexcitation is described. A prototype of an optical and X-ray image sensor, the equipment and software for reading and visualizing recorded information are analyzed.

This book systematically examines the results of an investigation of electronic and molecular processes on the surface of semiconductors, taking place at their interaction with particles of a gas environment or in the course of superficial alloying by atoms of metals. The main subject of the book is the analysis of interaction of semiconductors with foreign atoms and molecules from a gas environment and from beams of elements, bombarding a surface. This book consists of five chapters, including 13 tables, 122 figures and bibliography based on over 500 sources, including author's publications and data originally never published in English before. The book acquaints the reader with basic concepts and positions, used at the description of interaction of semiconductor surface with foreign atoms and molecules. Demonstration of opportunities arising from the usage of local and collective approaches to the analysis of electronic and molecular processes on a surface is useful though insufficient in determining the sensitivity for adsorption of a semiconductors' surface.