Fabrication and Cha r actcrization of Aluminum and Gallium Morroand Co-doped Zinc Oxide Thin Films by Radio Frequency Sputtering For photovoltaic Applications

Abstract

There is need to provide low resistivity ZnO transparent conducting thin films by radio frequency (rf) magnetron spunering technique for commercial photovoltaic applications. Rf magnetron spunering technique has comparative advantages such as ease of large-area deposition, low deposition temperature, high deposition rate, good adhesion between film and substrate: good surface uniformity, and simple equipment. However, ZnO thin films prepared b: r f magnetron sputtering face the challenge of stagnation in the lowest achievable resistivity values even for doped ZnO thin films. The lowest resistivity values are of the order 10.3 .ocm and 10" ncrn fur undoped and doped ZnO films, respectively. Aluminum (/'.1) and Gallium (Ga) elements are some of the leading dopants giving resistivity values onl , up to as low as 10--1 .oc Ill. lowering these values farther to the order 10': Dcm is critical for the commercial application of ZnO thin films in the photo voltaic industry. A further attempt to optimize electrical and optical properties for n-rype conducti. ity is suggested by co-doping ZnO with two metal elements and there is scanty research on it. The study is dedicated to fabrication of undoped (pure), IllOIlOdoped (AI, Ga) and Al-Ga co-doped ZnO thin films by rf magnetron spunering technique and their characterization for structural: electrical and optical properties. The best films will be tested for photovoltaic applications