The origin of persistent photoconductivity in compensated hydrogenated amorphous silicon

Abstract

The possible origins of persistent photoconductivity (PPC) in compensated hydrogenated amorphous silicon (a-Si:H) are reexamined by the numerical calculation. PPC behavior with the variation of defect density and active dopants concentration is compared with the previous experimental data. The results show that PPC cannot be induced by the defect generation only, but the deactivation of active boron should be included. The variation of PPC with light soaking is well explained by the deactivation of a boron acceptor and a defect generation induced by a hole capture. This result supports the thermal equilibrium, or the charge trapping model rather than the model based only on Staebler-Wronski effect. (C) 1997 Elsevier Science Ltd.