In-doped ZnO nanobelts were fabricated by thermal evaporation with assistance of gold catalyst. The nanobelts have high crystal quality and grow along [10 (1) over bar0] direction with (0001) dominated surface, and have an average In:Zn value of 1:30. A growth mechanism based on VLS is proposed to understand the nanobelts growth, explaining Au particles are only found at the ends of short narrow part of the nanobelts that are mostly uniform broad flat. The ZnO UV emission peak redshifting about 200 meV after doping gives an estimate of the carrier density in the doped ZnO nanobelts can be as high as 7 x 10(19) cm(-3). (C) 2004 Elsevier B.V. All rights reserved.