Fundamental concepts in the physics of amorphous semiconductors

We review some of the fundamental concepts which have been introduced into the field of amorphous semiconductors by Professor Sir Nevill Mott. These include the 8-N rule, variable range hopping, the Austin-Mott ac conductivity, the mobility edge, and the minimum metallic conductivity. We demonstrate that there are still severe problems, although there is no real alternative to Mott's concepts. (C) 1998 Elsevier Science B.V. All rights reserved.