Abstract
ZnO nanotubes array has been fabricated by a facile hydrothermal treatment of ZnO seeded silicon substrate in a sealed system. The as prepared ZnO nanotubes are single crystalline and have a [0001] preferential growth direction. Shape and size of the ZnO product is found to be sensitive to reaction conditions. Diffusion-limited crystal growth is proposed to explain the formation mechanism of ZnO nanotubes.