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

Abstract
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.