Tail states as sensitizing recombination centers for holes lifetime in a-Si:H

We have measured the dependence of the holes mobility-lifetime product on temperature under various light intensities in intrinsic a-Si:H. We find that this product exhibits thermal quenching which is accompanied by a superlinear light intensity dependence. Numerical calculations that we have carried out show that these results can be accounted for within the framework of the conventional recombination model. However, to yield such an agreement the capture coefficients for both charge carriers at the tail states must be smaller than the corresponding coefficients for the dangling bonds. Thus the sensitizing nature of the tail states is revealed.