Dominant recombination process in amorphous silicon alloys

We have critically examined experimental results on photoconductivity in hydrogenated amorphous silicon alloys to ascertain whether recombination at a single defect site (namely, the dangling bonds) or a continuous distribution of centers (dangling bonds together with other defects) provides a realistic model to explain the available experimental data. We find from both these results and from additional experimental data that, for good quality, low defect density material, room temperature recombination is controlled by a continuous distribution of states located between the trap-quasi-Fermi levels.