Photoluminescence of amorphous silicon at low temperatures: Computer simulation

Recombination and photoluminescence in amorphous silicon are studied using a computer simulation. It is shown that, in typical experimental situations, geminate recombination plays a minor role and most of the recombination events are distant-pair ones. The shapes and the positions of the luminescence peaks of time-resolved spectroscopy (TRS) and frequency-resolved spectroscopy (FRS) are studied and an approximate analytic theory to calculate them is derived. The width of the peaks obtained in our simulation is approximately two decades in time in the whole range of generation rates. These results are in good agreement with the experimental data as well as with our analytic theory. The possibility to observe a second, geminate, TRS and FRS peak in amorphous materials with strong polaron effects is discussed.