Defect emission in ZnO nanorods fabricated by hydrothermal method

Zinc oxide (ZnO) is a wide bandgap semiconductor which has great potential for a variety of practical applications. Hydrothermal growth of ZnO nanostructures is of particular interest because it is low cost, low temperature and environmentally friendly method. It is well-known that ZnO nanorods fabricated by hydrothermal method exhibit prominent defect related emission. In this work, we studied the morphology and optical properties of ZnO nanorods with different lengths fabricated with different seed layers. Effects of annealing at different temperatures and in different atmospheres were investigated. It was found that the defect emission was strongly affected by the annealing conditions. The origin of the defect emission and the observed differences after annealing are discussed.