We fabricated P-doped Si nanocrystallites embedded in SiO2 films and have investigated by photoluminescence (PL) spectroscopy and electron spin resonance (ESR) spectroscopy. The films were fabricated by annealing of P-doped SiOx films that were deposited by laser ablation of P2O5-coated Si targets in O-2 gas. Visible PL from nanocrystallites is enhanced at room temperature by 10 times as intense as undoped ones. ESR spectroscopy revealed that deposition at high energy density is effective for defect-free deposition. Furthermore, P atoms are found to be doped in the crystallites and electron-hole pairs bound to the P atoms are suggested to be responsible for the enhanced PL. In addition, we found a P-related center located at interface region between P-doped films of Si nanocrystallites and Si substrates, with a large hyperfine splitting of similar to80 G observed at 20 and 40 K. (C) 2002 Elsevier Science B.V. All rights reserved.