The past four decades have witnessed many inventions and developments in the field of an amorphous semiconductor such as chalcogenide glasses (Selenium, Tellurium, and Sulphur ) due to its wide applications in phase-change memory, switching, xerography, semiconductor devices, and optical memory devices, etc. Chalcogenide glasses are covalently bonded amorphous semiconductors either binary or cross-linked form. Selenium-based chalcogenide glasses exhibit phase-changing properties which make them potential industrial applications in making switching devices, phase change random memory devices (PRAM) and solar cells, etc. This book presents a comprehensive study on the important topic about amorphous semiconductor specially chalcogenide glasses materials and their characterization using different modern techniques such as X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Analysis by X-ray (EDX). Though this book is intended primarily for undergraduate and postgraduate students studying material science & engineering and nanotechnology, it is also useful for those who are pursuing research in material science and nanotechnology.