Geminate recombination in a-Si:H

The recombination kinetics in a-Si:H are studied by frequency resolved spectroscopy (FRS) and light-induced ESR (LESR) as a function of the generation rate G down to values as low as 10 16 cm −3 s −1 . For G 19 cm −3 s −1 the recombination kinetics are independent of the steady state carrier concentration n s which strongly indicates that in this range of low G geminate recombination prevails. A critical discussion of the FRS technique reveals that this method does not yield the lifetime distribution P( τ ) directly. The experimental FRS spectra are compared with predictions derived from a recent theory by Shklovskii et al. We show that this theory cannot account for the experimental results.