TRANSIENT PHOTOCONDUCTIVITY FROM THE STEADY-STATE IN UNDOPED AMORPHOUS-SILICON

In this study, experimental results of transient photoconductivity decay from the steady state in undoped amorphous silicon are presented. The results are explained within the framework of a theory of multiple trapping. It is found that the occupation function of electrons into the gap behaves as a quasi-Fermi distribution whose quasi-Fermi level moves from its steady-state position to the middle of the gap as time progresses. The rate equation for the free carrier density is numerically solved and compared with the experimental results. A good fit is obtained if one assumes the existence of a peak in the density of states. © 1990 IOP Publishing Ltd.