Effect of O2/Ar Ratio on Blue Photoluminescence Spectrum of Nanocrystalline ZnO Films

Nanocrystalline ZnO films were deposited on quartz substrates by radio-frequency magnetron sputtering (RFMS) method. The authors discussed the effect caused by the change in the ratio of oxygen to argon and quartz substrates temperature on the qualities of thin films and blue photoluminescence spectrum of ZnO films. Relationship between XRD intensity and FWHM of nanocrystalline Zno films at different ratio of O-2/Ar in processing was given. Photoluminescence spectrum (PL), absorption spectra (ABS) photoluminescence excitation spectrum (PLE) and X-ray diffraction pattern (XRD) of nanocrystalline ZnO film with excitation wavelength 300 nm were measured at room temperature. XRD pattern indicates that nanocrystalline ZnO film has a hexagonal wurtzite structure and is polycrystalline. Blue visible emission hands (430-460 nm) were observed, and its central wavelength is 445 nm. The relationship between PL area of integration and PL intensity of maximum of nanocrystalline ZnO films at different ratio of O-2/Ar in processing was given. The luminescence emission peak located at 450 nm corresponds to the transition from the shallow level of oxygen vacancy to valence band or the interstitial.