Amorphous semiconductors

The field of amorphous semiconductors has matured sufficiently within the last few years so that a meaningful breakdown into major areas of interest can be made. Broadly speaking, it can be broken down into the study of electronic properties and the study of effects based on the amorphous to crystalline phase transition. In the first category one is interested in answering questions regarding the effect of the loss of crystalline periodicity on a host of phenomena such as DC and AC conductivity, photoelectric effects, optical absorption, etc. In the area of phase transformation one is interested in the kinetics of the problem and in the properties of mixed crystalline-amorphous layers. These transformations can be made reversible by suitable electrical or light pulses and show promise in memory applications. The talk will summarize our knowledge of these two categories of the field.