A recombination model which took account of the spatial correlation of light-induced dangling bonds was considered. It was suggested that the creation of intimate dangling-bond pairs, which was expected to be more effective at lower illumination temperatures, could have a large effect upon recombination. In fact, alternative recombination channels which comprised tunnelling between close dangling bonds could appear to be predominant; even when the concentration of intimate dangling bond pairs was relatively low. Features of the photoconductivity of undoped amorphous hydrogenated material, such as the suppression of thermal quenching, a weaker temperature dependence and a linear light intensity dependence after light soaking, could be related to the creation of dangling-bond pairs and to their annealing with increasing temperature.

I.P.Zvyagin: Solid State Phenomena, 1995, 44-46, 765-72