Transport Properties of Amorphous Semiconductors

Abstract

The investigation of transport properties of amorphous semiconductors in the past has been much stimulated by the interest in possible technical applications. So far these expectations have only partly been fulfilled and at present mainly chalcogenide glasses are of some technical importance as photoreceptors, switching devices, memories etc. In the recent years, the tetrahedrally bonded amorphous semiconductors Ge and Si have probably become the most intensively studied disordered materials. This is a remarkable trend which can hardly be explained by technological reasons. These materials are the simplest disordered systems exhibiting only positional disorder and in the crystalline form these semiconductors are the best understood. The philosophy, therefore, is that particularly the investigation of amorphous Ge and Si offers a chance to find a profound understanding of the physics of the disordered state in general. In the following I will also follow this trend and therefore most of the presented experimental results will be on amorphous Ge and Si.