Stimulated ultraviolet emission from ZnO films annealed at high temperature

We report the results of an experimental investigation of optically pumped lasing in ZnO thin films deposited on a sapphire substrate by the metal organic chemical deposition technique. The mechanism of lasing in the case of an as-grown film and in case of an annealed film was investigated. After annealing, the crystalline quality was improved. Optically pumped lasing in a film annealed at 900 °C for 2 h was achieved at room temperature. The threshold of lasing was estimated to be about 30 kW/cm2.