Book excerpt: Amorphous chalcogenide semiconductors have commercial value and have many uses such as image formation, including x-rays, and high-definition TV pick up tubes. They have widespread application in the microelectronics industry and amorphous metallic alloys also have useful magnetic properties. This book focuses on their imaging applications and related properties. It examines the two groups of amorphous semiconductors that are of most commercial interest: the chalcogenide glasses the tetrahedrally bonded amorphous solids such as amorphous silicon, germanium and related alloys Both of these groups may be conveniently prepared in the form of thin/thick films which is of considerable importance in applications where large-area coverage of flat or curved surfaces of rigid or flexible materials is desirable such as in photovoltaic arrays, X-Ray sensors, display screens and photocopier drums. Provides information on the amorphous semiconductors that are of most commercial interest Presents the history of the commercial applications, the latest developments and future possibilities