Effects of Li and Mg doping on microstructure and properties of sol-gel ZnO thin films

Zinc oxide thin films doped with Li and Mg were prepared by the sol-gel method, and effects of doping on microstructure and electrical properties were examined. The doped films exhibited c-axis-orientation after final heating at 500°C for 30 min in flowing oxygen. The ZnO crystallite size increased by doping and the surface of the films became rougher. The current density of the films was reduced by doping probably due to the formation of acceptor levels (Li-doping) and the reduction of oxygen defects (Mg-doping). The film with a nominal composition of Zn0.85Li0.10Mg0.05O showed the lowest current density of 1.7×10−6 A cm−2 in the present study.