Above-band-gap photoluminescence from Si fine particles with oxide shell

Strong photoluminescence with sub-band-gap photon energies has been observed in fine Si particles prepared by the gas-evaporation technique. After surface oxidation, the Si particles show above-band-gap photoluminescence, the band tail covering the visible light region. The amount of the increased apparent band gap (0.3 eV) estimated from this blueshift can be explained by a quantum-size effect expected to be observed in Si quantum dots with a diameter of 50 Å.