Structural and optical properties of porous silicon at different porosities

Near edge x-ray absorption fine structure measurements and optical properties of porous silicon samples with different levels of porosity reveal the features of an Si atomic region. The sample which has the lowest porosity does not exhibit luminescence. Since Si substances with higher values of porosity exhibit luminescence, these samples are subjected to time resolved photoluminescence (PL) measurements. Time resolved PL measurements reveal that the high porosity samples possess large amount of passivating Si-H groups on the surface.