Influence of Na Doping on Structural and Optical Properties of (Na,Mg):ZnO Thin Films Prepared by Sol-Gel Process

Na element was introduced into preparation of Zn_0.8Mg_0.2O thin films, and high quality c-axis Na/Mg co-doped zinc oxide (ZnO) films with a nominal composition of Zn_0.8-xNa_xMg_0.2O were prepared on pyrex glass substrates by sol-gel spin-coating method. Effects of Na composition on structural and optical properties of the films were investigated. Experimental results show that both Na and Mg elements were successfully doped into the films even if Na is at low concentration. Na doped at low concentration can improve c-axis preferred orientation and crystallite quality of the pure Mg-doped Zn_0.8Mg_0.2O films, but the improvement and the crystallite size of the films decrease with the increase in the Na doping concentration.Zn_0.8-xNa_xMg_0.2O films with low Na concentration have an excellent UV luminescent characteristic.