Photoluminescence and EPR studies of porous silicon

The dependence of the photoluminescence, photoluminescence excitation spectra as well as EPR and SIMS of porous silicon on the electrochemical etching regimes have been studied. We have shown that the change of the photoluminescence intensity under ultra violet excitation correlates with the variation of the silicon oxide quantity in the porous layer. At the same time the variation of the photoluminescence intensity under visible excitation anticorrelates with the H and SiH contents in the samples. The appearance of three EPR-centers connected with the silicon oxide surface centers in aging process has been observed.