Anomalous temperature dependence of photoluminescence in porous silicon

We have studied the temperature dependence of luminescence in porous silicon between 10 and 300 K. We find that above 60 K the luminescence has a temperature dependence opposite in sign from that of the band gap. Using a Gaussian decomposition procedure we have identified three different processes which dominate the luminescence at different temperatures. With a knowledge of the temperature dependence of the relative intensities of the three components we explain the blue shift of the luminescence peak with increasing temperature. We also present arguments to show that the luminescence in porous silicon is due to a complex.