The persistent photoconductivity of hydrogenated amorphous material was reviewed. It was recalled that the 2 most likely models for the phenomenon were the dangling-bond model and the charge-trapping model. It was concluded that the charge-trapping reaction was the more likely explanation in the case of compensated amorphous Si films. In doping-modulated superlattices, the charge-trapping model was most likely for standard defect distributions, and the dangling-bond explanation was possible if a defect pool model was assumed. It was thought that the dangling-bond model was applicable to amorphous Si/SiO multi-layers, but it was not yet clear which model was correct for amorphous Si/SiNx multi-layers.

C.Lee: Solid State Phenomena, 1995, 44-46, 475-94