The evolution of the cathodoluminescent emission bands of porous silicon at 420-480 nm, 540 nm and 640 nm under oxidizing and inert atmosphere annealings has been investigated and correlated to the structural reconstruction of the porous silicon surface during the treatments. Dry oxidation at low temperature of 450 deg C determines a less defected bonding interface structure of the growing oxide matrix comp;aratively with an oxidation treatment at 1000 deg C. The optical absorption band at 883 cm~(-1) observed in the 1000 deg C oxidized porous silicon is correlated to the presence of the interface defect centers. The quenching of the 540 nm and 640 nm emission bands in the high temperature oxidized porous silicon results from nonradiative transitions in the associated defect levels.
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