Silicon nanoparticles are grown via ultra high vacuum chemical vapor deposition (UHV-CVD) on SiO2 and Si3N4 covered Si(I 0 0) substrates using disilane. Temperature programmed desorption spectra demonstrate the presence of H-2 and SiO desorption features at 770 and 900K, respectively, which are in the 750-1000K temperature range that is typical for nanoparticle growth via CVD. The lower temperature limit (similar to750 K) for nanoparticle growth is related to hydrogen desorption from the nanoparticle surface just as in epitaxial growth. SiO desorption is shown to hinder silicon adatom accumulation and nanoparticle nucleation on SiO2 at temperatures as low as 875 K, giving an upper temperature limit for dense nanoparticle growth. Optimum conditions for nanoparticle growth on SiO, are found within this narrow temperature window (750-875 K), and densities up to 8 x 10(11) cm(-2) are obtained within. Depletion of surface silicon is not observed on Si3N4 substrates, and this allows high-density nanoparticles to be grown at much higher temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.