Thermal quenching of defect photoluminescence and recombination rates of electron–hole pairs in a-Si:H

Temperature variation of non-radiative recombination rate, competing with defect photoluminescence (PL), has been obtained from characteristic lifetimes estimated from experiments by means of frequency resolved spectroscopy (FRS) for a-Si:H films after illumination of pulsed light. Conventional interpretation of thermal quenching of the PL in a-Si:H, where the non-radiative recombination rate has an activation-type temperature dependence and the radiative recombination rate is independent of the temperature, is not suitable to explain the experimental results of the defect PL. The temperature variation of the non-radiative recombination rate obtained for the defect PL is well described by a theory of Englman and Jortner for the case of strong electron–phonon coupling.