The light intensity exponent of the minority carrier lifetime and the mobility gap states in a-Si:H

We recently gave physical arguments that the recombination in a single type of dangling bond centers will yield a zero value for the light intensity exponent of the minority carriers, λ. We then concluded that the observed λ ≠ 0 value in a-Si:H indicates the presence of other states in its mobility gap. In this paper, we substantiate those arguments by an analytic proof, by computer simulations and by considering our recent experimental findings on the temperature dependence of λ. In particular, we show that in an n-type photoconductor the dangling bond acts as a single acceptor-like recombination center.