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-3s-1. For G < 10(19) cm-3s-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(tau) 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.