Lasing characteristics of ZnO nanosheet excited by ultraviolet laser beam

The lasing characteristics of ZnO nanosheets were investigated for an application to ultraviolet laser diode. ZnO nanosheets were synthesized on a silicon substrate by a CVD method, and then those ZnO nanosheets were examined by a photoluminescence method with a third-harmonic Nd:YAG laser (355 nm, 5 ns). The observed emission spectra showed the obvious lasing characteristics having mode structure and a threshold for lasing. The threshold power density of a ZnO nanosheet was measured to be 40 kW/cm2, and it would be low enough to be oscillated by an electrical pumping for ultraviolet laser diode.