Crystalline ZnO nanoparticles were synthesized on Si substrates with or without a Au catalyst by a chemical vapor deposition (CVD) method using ZnS as the source material. The average sizes are in the range of 40-200 nm and the densities of 10(4)-10(10) cm(-2). In the absence of an Au catalyst, the average nanoparticle size firstly decreases and then increases with increasing substrate temperature while the nanoparticle density decreases as the substrate temperature increases. In the presence of an An catalyst, ZnO nanoparticles only grow when the substrate temperature is higher than 300 degreesC and the higher the substrate temperature the denser the nanoparticles are deposited. The density of the ZnO nanoparticles grown on a Si (111) substrate is higher than that on a Si (100) substrate with or without An catalyst. (C) 2003 Elsevier B.V. All rights reserved.