PREPARATION AND PROPERTIES OF ANODIZED AMORPHOUS-SILICON

Boron-doped amorphous silicon layers deposited by glow-discharge on co nductive substrates have been electrochemically etched in the same hyd rofluoric acid solutions that yield intense visible light-emitting por ous layers from crystalline silicon. We show that both as-etched and e lectro-oxidized a-Si:H films are luminescent at room temperature in th e visible and near infrared and we report electroluminescence spectra recorded during the anodic oxidation. The room-temperature photolumine scence decay times of a few tens of ys are longer at larger emission w avelengths and comparable to those of porous wafers obtained in the sa me way. In both cases, the decay pattern is shown to be qualitatively distinct from that observed in amorphous silicon-based alloys.