Deposition of sub-monolayer silicon on SiO2/Si(1 0 0) greatly facilitates nucleation in subsequent thermal chemical vapor deposition (CVD) of silicon nanoparticles. Sub-monolayer seeding is accomplished using silicon atoms generated via disilane decomposition over a hot tungsten filament. The hot-wire process is nonselective towards deposition on silicon and SiO2, is insensitive to surface temperature below 825 K, and gives controlled coverages well below 1 ML. Thermal CVD of nanoparticles at 1 x 10(-4) Torr disilane and temperatures ranging from 825 to 925 K was studied over SiO2/Si(1 0 0) surfaces that had been subjected to predeposition of Si or were bare. Seeding of the SiO2 surface with as little as 0.01 ML is shown to double the nanoparticle density at 825 K, and densities are increased twenty fold at 875 K after seeding the surface with 30% of a monolayer. (C) 2002 Elsevier Science B.V. All rights reserved.