Time-resolved luminescence spectrum and radiation recombination progress in surface and core of porous silicon

Time-resolved luminescence spectra (TRLS) of porous silicon (PS) at the delay time range of 10(-9)-10(-6) second were investigated. The luminescence spectra include : the blue zone with decay time about nanoseconds and the red one with longer decay time. Recombination mechanisms in the core and in the surface states were used to explain this experimental result. Especially, the existence of discrete peaks in blue zone shows that the luminescence in this zone is due to nano-scale crystals.