The Growth of Surface Textured Aluminum Doped ZnO Films for a-Si Solar Cells by RF Magnetron Sputtering At Low Temperature

Abstract

AbstractTransparent Conducting Oxide films are essential for all kind of thin film solar cells. Doped Zinc Oxide (ZnO) in particular has several advantages when compared to other TCOs. It is stable in a hydrogen plasma and it acts as a diffusion barrier with respect to impurities from the substrate. In this work results on textured ZnO films deposited by RF magnetron sputtering are presented. The dependence of the film properties on the RF power, the substrate temperature and the water-vapor partial pressure added to the argon atmosphere has been investigated. We have found that high quality textured aluminum doped ZnO (ZnO:AI) films can be grown at low temperatures (150 °C) using the sputtering technique. Textured surfaces show two types of surface morphology; columnar and granular, depending on the deposition conditions. The ZnO:AI films seem to undergo a structural transition from hexagonal (mostly columnar appearance) to cubic structure (mostly granular appearance).