Excitation Dependence of Photoluminescence in the 1.5-1.6 μm Wavelength Region from Grown Dislocation-Rich Si Layers

We study photoluminescence (PL) in the 1.5-1.6 μm wavelength region from dislocation-rich Si layers grown using the oxidized Si surfaces. The obtained excitation dependences of the PL intensities are interpreted on the base of a model of the electronic structure that consists of the shallow dislocation-induced conduction sub-band and deep levels located about 0.3 eV above the valence band edge. At low temperature and low excitation conditions the dependences are described well by mean of the Shockley-Read-Hall statistics for the carrier recombination via deep states. The PL data at high excitation conditions suggest that the dominating process that limits the increase in the excess carrier concentration is Auger recombination in which one of three carriers involved into the recombination event is from the deep states. A blue shift of the dislocation-related PL peak with increasing excitation intensity is observed, which is associated with changes in the occupancy of the deep states.