A pulsed KrF excimer laser of irradiance of about 10(8) W/cm(2) was utilized to synthesize Si nanocrystals on SiO2/Si substrates. The results were compared with that ones obtained by applying low bias voltage to Si(1 0 0) target in order to control the kinetic energy of plasma ions. Glancing incidence X-ray diffraction spectra indicate the presence of silicon crystalline phases, i.e. (1 1 1) and (2 2 0), on SiO2/Si substrates. The average Si nanocrystal size was estimated to be about 45 nm by using the Debye-Scherrer formula. Scanning electron microscopy and atomic force microscopy images showed the presence of nanoparticles of different size and shape. Their distribution exhibits a maximum concentration at 49 nm and a fraction of 14% at 15 nm. (C) 2008 Elsevier B. V. All rights reserved.