Highly split, visible light emissions at room temperature were observed in the range from 335 to 650 nm in silicon‐rich oxide films deposited in the plasma phase of a mixture of silane and oxygen. The mechanism of the light emissions is classified into two categories. The photoluminescence bands at both 365 and 469 nm are related to the intrinsic defects of theE′ center and the neutral oxygen vacancy, respectively. However, the relatively sharp peaks at 403 and 535 nm are correlated with the development of polycrystalline core of Si‐enriched parts. ©1996 American Institute of Physics.