Influence of substrate temperature on the orientation and optical properties of sputtered ZnO films

The influence of substrate temperature on the orientation and optical properties of sputtered ZnO films is studied in the paper. X-ray diffraction (XRD) demonstrates that at the substrate temperature of 350 °C, (002) and (004) diffraction peaks of ZnO films have occurred. It reveals that highly c-axis preferential orientation of ZnO film with wurtzite phase was fabricated at 350 °C. Besides, the red shift of the absorption band edge, as the substrate temperature increases, is attributed to the high O 2 vapour pressure of ZnO, which causes the vacancies in ZnO films. Meanwhile, photoluminescence (PL) spectrum of the transparent ZnO films deposited at 350 °C shows the intrinsic emission peak and a broad green emission band.