Wavelength-tunable and high-temperature lasing in ZnMgO nanoneedles

Zn 1 − x Mg x O nanoneedles were prepared by an ion-beam technique on Zn1−xMgxO thin films with Mg contents of up to 21at.%. The photoluminescence emission energies of the Zn1−xMgxO nanoneedles measured at room temperature increased monotonically with Mg contents and it reached 3.6eV when x=0.21. Random laser action was observed in the Zn1−xMgxO nanoneedles with x⩽0.1 at temperature ranging from 300to470K under 355nm optical excitation. The characteristic temperature of the Zn1−xMgxO nanoneedles was determined to be 84K. The high-temperature lasing of the Zn1−xMgxO nanoneedles are attributed to the high crystal quality of the nanoneedles, enhancement of oscillator strength in nanostructures, and a self-compensation mechanism in random laser cavities.