High-Field Electron Transport and Hot Electron Phenomena in Hydrogenated Amorphous Silicon Films

Abstract

Electron transport under high electric field in hydrogenated amorphous silicon (a-Si:H) films has been investigated by means of time-of-flight (TOF) measurements. The drift mobility µ increased with increasing applied electric field E accompanied by a simultaneous increase in the dispersion parameter α resulting in nondispersive transport. The electron thermal runaway breakdown field E* with optical carrier injection decreased with increasing ambient temperature T a in accordance with the hot electron theory in amorphous solids [H. Fröhlich: Proc. R. Soc. London A 118 (1947) 521]. The field dependencies of µ and α are also explained by taking account of the increase in the effective electron temperature (hot electron phenomenon) at high field in the theory of dispersive transport.