The nanocrystalline silicon films were prepared by pulsed laser ablation in the gas mixture of high-purity inert gases (He/Ar, Ne/Ar or He/Ne) under the deposition pressure of 10 Pa. The microstructural properties of the films produced under various mixed ratios were characterized by scanning electron microscopy, X-ray diffraction and Raman. The result shows that the closer to the Si atomic mass the average atomic mass of the ambient gas, the smaller the average size of the Si nanoparticles, which may be attributed to more effective energy transfer among the ambient atoms and Si atoms. (c) 2006 Elsevier B.V. All rights reserved.