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 EPL, 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 104 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.