Role of Heterogeneities in Staebler-Wronski Effect

The effect of light soaking (LS) on the properties of hydrogenated amorphous silicon presents many challenging puzzles. Some of them are discussed here, along with their present status. In particular the role of the heterogeneities in LS is examined. We find that for the majority of the solved as well unsolved puzzles the long range potential fluctuations arising from the heterogeneities in the films can provide answers which look quite plausible.