ABSTRACT
To accomplish a high-performance zinc oxide (ZnO)- based optoelectronic device, the formation of a quality contact between ZnO film and metal is essential. Up to date, sputtering technology is a commonly used system for large-area and cost-efficiency ZnOlayered fabrication in application on the optoelectronic devices. However, limited reports on the ZnO-based Schottky diodes purely prepared using sputtering technology since significant defects formed in the films are inevitable due to the ion-bombardment damage effect (Y. Caglar et al. 2008). Accordingly, various ZnO surface passivation processes were processed to achieve a quality ZnO-based Schottky diode (S. H. Kim et al. 2005; Q. L. Gu et al. 2008). Among theses surface treatments, liquid-phase process which has the simple and non-vacuum advantages over others seems to be the best process method. Although reports had demonstrated that the improvement of the resulting metal/ZnO contact was attributed to the surface state passivation (B. T. Lai et al. 2010; Y. J. Lin et al. 2009), the dominated factor responsible for the surface passivation still was indefinite. In this work, with the aim to extract the passivated mechanism of the sputtered-ZnO films, using the dilute H2O2 and (NH4)2Sx solutions, respectively, the material and optical properties of these passivated-ZnO films were comprehensive investigated through the x-ray photoelectron spectroscopy (XPS) and room-temperature photoluminescence (RTPL) measurements.
