Lasing in whispering gallery mode in ZnO nanonails

We report on the observation of ultraviolet lasing in optically pumped ZnO nanonails synthesized by thermal chemical vapor deposition method. The lasing threshold was found to be 17 MW cm(-2). Very sharp emission peaks (full width at half maximum of 0.08 nm) were observed in the emission spectrum, indicating a high Q factor of the cavity formed by the hexagonally shaped nanonail head. The analysis of the lasing spectra strongly suggests the whispering gallery mode lasing from a hexagonally shaped head of the single ZnO nanonail. (C) 2006 American Institute of Physics.