Photoconductivity in compensated a-Si:H and the effect of bias light on the drift mobility

Abstract

We measured the photoconductivity σ p of compensated hydrogenated amorphous silicon (a-Si:H) between 4.2 and 400K. The P H 3/ SiH 4 = B 2 H 6/ SiH 4 doping ratios ranged from 2.5 × 10 −6 to 10 −2. Potential fluctuations strongly degrade σ p. Subgap absorption and defect concentration are unreliable indicators for material quality. The drift mobility obtained from the initial decay of σ p was found to increase at surprisingly small bias light intensities.