Switching in amorphous devices

Electrical switching of a kind can be observed in a great variety of materials in many different forms and structures. Much the most reproducible switching is observed, however, in small and geometrically well-defined devices fabricated from thin films of certain amorphous semiconductors. This paper is concerned with such devices. The general features of electrical switching are first reviewed, followed by a more detailed account of recent work in the authors' own laboratories on digital and analogue switching in hydrogenated amorphous silicon.