New model of the temperature dependence of the 1.4-eV emission band of amorphous silicon

Abstract

Time-resolved measurements of the quenching of the long decay components of the 1.4-eV luminescence of $a$-Si:H show that the mechanisms of thermally induced lifetime redistribution and thermal quenching are distinct. We identify the mechanisms as, respectively, electron and hole diffusion. This model implies distant-pair kinetics for the photoluminescence. Comparison of the activation energies found from the photoluminescence with those of the mobility suggest that the mobility is due, not to thermal excitation to a mobility edge, but to percolation in potential fluctuations of a length of some 100 Å.