High-Temperature Lasing Characteristics of ZnO Epilayers

Coherent random lasing has been observed inside nanostructured ZnO epilayers up to 570 K. The corresponding characteristic temperature is ∼127 K. The confinement of excited carriers inside ZnO grains and the size flexibility of the random cavities maintain optical gain at high temperatures. This unique behavior will lead to the development of novel ZnO UV lasers tunable over a wide wavelength range by controlling the substrate temperature.