Preparation and properties of anodized amorphous silicon

Abstract Boron-doped amorphous silicon layers deposited by glow-discharge on conductive substrates have been electrochemically etched in the same hydrofluoric acid solutions that yield intense visible light-emitting porous layers from crystalline silicon. We show that both as-etched and electro-oxidized a-Si:H films are luminescent at room temperature in the visible and near infrared and we report electroluminescence spectra recorded during the anodic oxidation. The room-temperature photoluminescence decay times of a few tens of μs are longer at larger emission wavelengths and comparable to those of porous wafers obtained in the same way. In both cases, the decay pattern is shown to be qualitatively distinct from that observed in amorphous silicon-based alloys.