Understanding the photoluminescence over 13-decade lifetime distribution in a-Si:H

Wideband quadrature frequency resolved spectroscopy (QFRS) expanded from 2 ns to 160 s revealed that the triple-peaked lifetime distribution observed in the photoluminescence (PL) of a-Si:H consists of the well-known double-peak structure and a newly identified third component. By the exploring dependence of the lifetime distribution on the generation rate G, temperature T, PL emission energy E-PL, PL excitation energy Ex and external magnetic field, the former is assigned to excitonic recombination and the latter to distant-pair (DP) or nongeminate recombination. The DP component gives the same sublinear G and T dependence as light-induced electron spin resonance (LESR) results. The present paper also shows that the residual PL decay in a-Si:H persists for more than 10(4)S, which corresponds the DP component and agrees with the LESR results. The residual PL decay reveals that the DP recombination kinetics is monomolecular at low T and low G. (c) 2006 Elsevier B.V. All rights reserved.