Optical property and aging effect of ZnO thin films

ZnO thin films are deposited on glass substrates at different temperatures in the pulsed laser deposition (PLD) system. By measurements of X-ray diffraction (XRD) and Photoluminescence (PL), 400degreesC-500degreesC is found to be the adapted temperature for its structure and optical properties. At the adapted experimental condition ZnO thin films are deposited. The as-deposited thin films are attached by GaAs wafers and annealed at different temperatures and for different times. photoluminescence measurements are carried out to find the As doping and annealing effects. There exist two PL emission peaks in all samples, and its annealing decreases the intensity of the green emission. The aging effect is found in ZnO thin films by PL measurements. The green emission peak decreases, and the near band emission peak is enhanced because of the compensation of the oxygen vacancies in thin films. As far as we know, the aging effect in ZnO thin films is found for the first time.