HIGH-FIELD ELECTRON-TRANSPORT AND HOT-ELECTRON PHENOMENA IN HYDROGENATED AMORPHOUS-SILICON FILMS

Electron transport under high electric field in hydrogenated amorphous silicon (a-Si:H) films has been investigated by means of time-of-light (TOF) measurements. The drift mobility mu increased with increasing applied electric field E accompanied by a simultaneous increase in the dispersion parameter alpha 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. Frohlich: Proc, R. Sec. London A 118 (1947) 521]. The held dependencies of mu and alpha 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.