Photoluminescence of porous silicon exposed to ambient air

The room‐temperature photoluminescence and structure were studied concerning porous silicon which was exposed to ambient air. Water vapor in ambient air gradually oxidized the surface of the porous silicon with developing Si—O—Si bonds. This room‐temperature oxidation progressively replaced an unstable H‐passivated surface with a more stable O‐passivated surface, dramatically increasing the intensity of the photoluminescence.