Early photoluminescence decay ina-Si: H

Photoluminescence (PL) decay in $a$-Si: H has been measured in the time regime of 0.5-40 nsec, and the dependence upon temperature, emission energy, and excitation energy has been systematically investigated. The subnanosecond time resolution was achieved by using a single-photon-counting detection system in conjunction with synchrotron radiation as the light source. We present an analysis method for quantitatively characterizing the PL decay in terms of a model function, with which the experimental broadening is removed by deconvolution. Deconvoluted PL decay measured at different emission energies is rearranged to yield the time-resolved PL emission spectrum. The behavior of the PL emission spectrum, and the variations of the decay with temperature, emission energy, and excitation energy, provide much insight into the recombination kinetics of photogenerated electron-hole pairs on the nanosecond time scale. The experimental results are interpreted in terms of specific physical processes.