Intense laser irradiation has been used to anneal porous silicon. In situ Raman spectroscopy and photoluminescence (PL) spectroscopies have been used as probes of the silicon particle sizes and temperatures, and the resulting light emission of porous silicon. Once annealed, the PL of porous silicon while at 830 °C exhibited no PL energy shift from its 300-K position. Since the gap of silicon redshifts by 0.29 eV at 830 °C, this red PL cannot be the property of the Si particles. A model involving the presence of nonbridging oxygen hole centers has been suggested to account for this PL.

• Received 20 October 1993

DOI:https://doi.org/10.1103/PhysRevB.49.2238