FECT

Abstract: The term, persistent photocurrent (PPC), is the long-term residual photocurrent after ceasing photo-illumination in photoconductive materials, which induces a delay of response time in photo-devices. Although the PPC  in photosensitive semiconductors is known to be dominated by dispersive reaction kinetics which produce the power low decay, t^-b, or the stretched exponential functional (SEF) decay, exp(-Ct^-b), where  b (< 1.0) is called the dispersion parameter, the origin for the occurrence of the dispersive reaction is not clear. Origin of the dispersive nature in long-term photocurrent decay is discussed in photosensitive semiconductors such as hydrogenated amorphous silicon (a-Si:H), amorphous chalcogenides (a-Chs), and in III–V semiconductors. It is shown that the recombination path of excess photocarriers play the dominant role in these materials.

Keywords: persistent photocurrent, dispersive reaction, amorphous semiconductors, DX centre.