Photo-induced charge transport in SiO2 films containing Si nanocrystals

Photo-induced charge transport is reported in metal-insulator-semiconductor structures containing Si nanocrystals produced by ion implantion and annealing. Successive shifts in current-voltage (I-V) and capacitance-voltage (C-V) curves are shown to be induced by ultra-violet (UV) light exposure under no bias. These shifts are shown to be enhanced by the application of a negative bias voltage during illumination. The application of a positive bias voltage during illumination is shown to reverse the direction of the shifts in both the I-V and C-V curves. This behaviour can be explained by charging of the nanocrystals induced by photoionization of electrons and charge movements in the insulator layer. (C) 2001 Academic Press.