Random lasing action of randomly assembled ZnO nanowires with MgO coating.

Lasing characteristics of randomly assembled ZnO nanowires (NWs) coated with different thickness of MgO layers are investigated. It is found that the MgO coated randomly assembled ZnO NWs demonstrate random lasing action and the formation of coherent optical feedback is dependent on the thickness of MgO coating. Pump threshold of the MgO coated randomly assembled ZnO NWs increases with the increase of MgO thickness. Nevertheless, the appropriate use of MgO coating can reduce the pump threshold by approximately 30% and the corresponding characteristic temperature can be improved by 28 K.