AbstractWe report on random laser emission in pulsed laser deposited nanocrystalline ZnO thin films. The deposition was done on silicon and glass substrates in ambient oxygen pressure ranging from 10 mTorr to 1 Torr at room temperature. The deposited films were characterized using XRD, RBS, PL and AFM. The films grown at pressures less than 300 mTorr are found to be preferentially oriented along (002) plane. Morphology of the films deposited at different background pressures showed that the films deposited at lower pressures are significantly smoother than those at higher back ground pressure. PL intensity depends on the stoichiometry of the films and hence on oxygen pressure. Laser action was observed on optically pumping the films with 355 nm radiation. At excitation intensity above threshold, very narrow peaks are observed in the emission spectrum. The dependence of the laser emission on the size of nanocrystallites at different pressures of the ambient gas is presented.
Room-temperature ultraviolet laser emission from self-assembled ZnO microcrystallite thin films