Low-temperature synthesis and room temperature ultraviolet lasing of nanocrystalline ZnO films

Nanocrystalline ZnO films were fabricated via a simple method involving the oxidation of Zn films at a remarkably low temperature of 380 °C. X-ray diffraction study confirmed that the Zn films were completely oxidized even at the low temperature of 380 °C and the ZnO films fabricated were of polycrystalline wurtzite structure. Room temperature optical pumping using a frequency-quintupled Q-switched Nd:YAG laser (=213 nm) exhibited that sharp peaks at around 3.12 eV emerged above excitation powers of 7 MW/cm², demonstrating lasing in the ZnO films. These results represent that the process is a simple, promising approach for fabricating ZnO of sufficient optical performance for use as ultraviolet (UV) light emitters and an alternative UV laser source; both are key components in short-wavelength photonic devices. PACS 81.07.Bc; 61.46.+w; 68.55.-a; 78.55.Et; 42.55.Px