Effect of the charge state of defects on the light-induced kinetics of the photoconductivity of amorphous hydrated silicon

The photoconductivity and defect density in films of nondoped a-Si:H soaked with light (W=114 mW/cm2, λ<0.9 µm) for 5 h were investigated. It is shown that σph ~ t-γ and ND ~ tβ, where γ>β or γ⋍β, depending on the position of the Fermi level prior to light soaking, i.e., depending on the charge state of the defects: D− and D0 or D+ and D0. It is also shown that the light-induced kinetics of σph is affected by a transition of the defects into the D0 state because of a corresponding shift of the Fermi level during light soaking.