Potential fluctuations and Staebler-Wronski effect

In hydrogenated amorphous silicon (a-Si:H), non homogeneous distribution of hydrogen and random distribution of localized charged centers give rise to the long range potential fluctuations which influence the electronic transport in a-Si:H. We study the effect of light soaking (Staebler-Wronski Effect: SWE) on lithium doped a-Si:H by measuring conductivity and thermopower. We relate the change in transport properties after light soaking to an increase in potential fluctuations. We propose a model which incorporates recombination of charge carriers in presence of these potential fluctuations to explain our observations.