It was found that high-intensity (9W/cm2) red-light soaking (120h) of amorphous hydrogenated material at 65C yielded no detectable H diffusion in tracer experiments. A new upper bound on the light-induced diffusion coefficient was found at a temperature that was so low that thermal diffusion was negligible. The null result which was found here was incompatible with models in which H emission from Si-H bonds was assumed to be proportional to both the light intensity and the metastable defect creation rate. However, this result was compatible with a model in which both H emission and metastable defect creation were proportional to the product of the free electron and hole densities. This implied that fewer than 500 H emissions occurred per metastable defect that was created

H.M.Branz, J.Bullock, S.Asher, H.Gleskova, S.Wagner: Journal of Non-Crystalline Solids, 1996, 198-200[1], 441-4