Photoluminescence and ultraviolet laser emission from nanocrystalline ZnO thin films

Abstract
We report on photoluminescence and ultraviolet laser emission from ZnO pellets and thin films of ZnO. Laser emission from disordered polycrystalline thin films and pellets was observed in all directions. ZnO films were deposited on glass substrate at room temperature in various ambient gas pressures of oxygen using the pulsed laser deposition technique. The dependence of laser emission on the size of nanocrystallites observed at different pressures of ambient gas is discussed. Photoluminescence spectra depend on the stoichiometry and the microstructure of the film.