Effect of ITO film deposition conditions on ITO and CdS films of semiconductor solar cells

Inorganic metal chalcogenide compounds based thin-film solar cells are regarded as most promising candidates for film power modules due to their high efficiencies with low cost. From top to bottom, the semiconductor thin film solar cell is made up of a metal layer, an absorber material, a buffer layer, and a transparent conducting oxide (TCO). Indium tin oxide (ITO) is a common material for transparent conducting films used as a front contact layer on solar cells. Although extensive studies have been performed on the deposition and properties of ITO films, few studies focused on the effect of the sputtering deposition conditions of ITO on the buffer layer. In this study, ITO thin films were deposited on soda-lime glass (SLG) by conventional RF-magnetron sputtering. The dependence of the electrical and crystalline properties on different substrate temperature, different RF power and different introducing rate of oxygen was investigated. The deposition conditions of ITO not only have influences on the structure and properties of ITO but also affect the buffer layer underneath. Therefore, we investigated the effect of ITO deposition parameters on the crystallization and electrical and optical properties of sputtered CdS films and, in turn, on the resulting device characteristics.