Analysis of the photoconductive decay from a trapping perspective

Abstract

The photoconductive decay is analysed by identifying the traps which interact with the excess free carrier density in the initial part of the decay. The analysis may account for the experimental observation that decay times for amorphous semiconductors are much shorter than expected from the traditional analysis, in which the decay time is calculated from the trapped carrier density in the band tail or the position of the quasi-Fermi energy. The overestimate of the role of those states which contain trapped carriers but to which free carrier trapping occurs on a longer time scale than recombination is assessed. Our considerations are supported by the numerical solution of the time-dependent rate equations.