R. F. power dependence of the Staebler-Wronski effect

Abstract

The Staebler-Wronski effect has been investigated in glow-discharge-deposited hydrogenated amorphous silicon films (about 1 μm thick) grown at different r.f. powers. The samples, exposed to visible light of intensity 350 mW cm^-2, showed a change, in both the activation energies for conduction and the pre-exponential factors. The activation energies changed from 0.83-1.05 eV in as-deposited annealed films to 1.03-1.15 eV for exposed films whereas the changes in the pre-exponential factors were from 5.0 × 10⁴-4.3 × 10⁷ Ω^-1 cm^-1 to 9.3 × 10⁵-2.3 × 10⁷ Ω^-1 cm^-1. Both of the constants for Meyer-Neldel rule also showed a change from 3.46 × 10^-7 Ω^-1 cm^-1 and 30.91 eV^-1 to 1.23 × 10^-10 Ω^-1 c^-1 and 36.62 eV^-1. The pre-exponential factors and the activation energies showed a peak for films deposited at 50 W and the rate of change of the density of dangling bonds with illumination time showed a minimum for the same film. The changes in dark conductivity and photoconductivities from the annealed to the exposed state were found to be at a maximum for samples deposited at 5 W.