Oriented single crystalline ZnO nanobelts have been synthesized through a hydrothermal method. Structural characterizations using X-ray diffraction and transmission electron microscopy revealed that the ZnO nanobelts possess wurtzite structure with a c-axis growth orientation and are faceted in (1120) and (0110) atomic planes. The growth mechanism of the nanobelts was discussed. Temperature-dependent photoluminescence measurement of the annealed ZnO nanobelts has been carried out and it showed that both the excitonic emission and the deep level emissions increased with decreasing temperature. ; Department of Applied Physics