High-density GaN nanorods with uniform diameters and lengths were successfully grown on Au-coated silicon substrate, The diameters were in the range of 50-80 nm, and the lengths ranged from 1 to 2 mum. A significant feature is that each nanorod was attached with nanoparticle at its very end, which is consistent with the vapor liquid-solid (VLS) growth mechanism. It was also found that the as-grown final product is strongly dependent on the thickness of the An thin film coated on the silicon substrate. According to the experimental results, we proposed that the catalytic activity of Gold is determined by the size of An particles, and just very small Au clusters exhibit effective reactivity in the growth of GaN one-dimensional nanostructures. (C) 2004 Elsevier B.V. All rights reserved.