ZnO films were deposited on c-plane sapphire substrates in Ar atmosphere by rf magnetron sputtering and were post-annealed at 400 °C in green gas (95% N2 + 5% H2). The properties of the as-grown and annealed films have been characterized by X-ray diffraction (XRD), Rutherford backscattering (RBS), elastic recoil detection analysis (ERDA), Hall measurement and photoluminescence spectra. XRD studies confirmed the variation in strain and an improvement in crystallinity. From RBS and ERDA analysis, the presence of H atoms on the surface of the as-grown ZnO films was evidenced. Annealing in green gas increased the amount of H in the film. Compared with the as-grown films, the ultra exciting intensity obviously decreases in the annealed films and new optical active centres in the blue/violet (∼3.0 eV) and red (∼1.9) regions are emerged in the PL spectrum. The positive sign of Hall coefficient confirmed the low p-type conductivity in the as grown films, which was improved after annealing. However, the p-type conductivity was not stable, especially for the annealed sample it changes from p type to n type after 9 days.
Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.