Model for the temperature dependence of photoluminescence ina-Si:H and related materials

We develop a model which interprets the temperature dependence of the intensity of the photoluminescence peak near 1.4 eV observed in $a$-Si:H and related materials in terms of a distribution of activation energies for nonradiative recombination. We find that the width and energy position of the maximum of the distribution correlates well with the spectral width of the luminescence and the activation energy for the drift mobility of photoproduced carriers. This correlation holds for sputtered and glow discharge $a$-Si:H, and $a$-Si:O, $a$-Si:H:O, $a$-Si:H:F, and $a-{\mathrm{Si}}_{1-x}{\mathrm{Ge}}_x$:H. Consistent differences between the distributions for sputtered and glow discharge $a$-Si:H, and between $a$-Si:H and $a$-Si:H:O are obtained. We conclude that changes in the luminescence spectral width and temperature-quenching behavior among these materials reflect changes in the distribution of localized states below the conduction-band edge.