Applying laser ablation technique, we have synthesized two types of Si
O2 films that included nanometer-sized Si particles. One is synthesize
d by alternative deposition of Si nanoparticle layers and SiO, lavers.
The synthesized film exhibits red photoluminescence (PL) with a peak
energy below 1.5 eV. The other is a SiO2 film in which Si nanocrystall
ites precipitate. The films were synthesized by annealing at 1000 degr
ees C of SiOx films which are formed by laser ablation in diluted O-2
gas. The films exhibit PL with peak energies of 1.5 eV, 2.2 eV and 2.7
eV. We find that there is a narrow range of composition for efficient
1.5-eV PL. (C) 1998 Elsevier Science B.V.