A reduction in the Staebler-Wronski effect observed in low H content a-Si:H films deposited by the hot wire technique

Abstract

Constant photocurrent (CPM) and steady state photograting (SSPG) measurements have been performed on a series of hot wire (HW) and glow discharge (GD) hydrogenated amorphous silicon (a‐Si:H) films, where the substrate temperature was varied in each case to affect the bonded H content. A reduction in the magnitude of the Staebler‐Wronski effect, as observed by CPM after saturation light soaking, is seen when the H content is reduced in both sets of samples, but the lowest saturated CPM values and the highest SSPG diffusion lengths measured after saturation occur for HW films having H contents in the range 1‐4 at.%. Although correlations exist between the number of excess defects produced by saturation light soaking and microscopic parameters such as the H content and the optical bandgap, there is not a simple correspondece for both sets of samples. This suggests that the Staebler‐Wronski saturation may be influenced in part by the film microstructure.