Annealing effects in non-polar ZnMgO thin films fabricated by PLD

ZnMgO thin films deposited on Si (111) substrates by pulsed laser deposition at 300°C were annealed at different temperatures from 400 to 800°C in air. Non-polar films with (110) orientation have been obtained. The thin film annealed at 500°C shows the co-existence of (002), (200) and (110) orientations according to X-ray diffraction observation, which illustrated that Mg has been incorporated into ZnO. Scanning electron microscopy images and energy dispersive X-ray revealed the variation of surface morphology and element content. The largest band gap value has been determined to be 4·31 eV when the film was annealed at 700°C. The typical peaks of Zn–O and Mg–O bonds were observed in the IR spectrum. The shift of UV peaks in photoluminescence spectra emerged due to the increase in Mg doping as the annealing temperature increases.