Transparent electronics is an advanced technology concerning the realization of invisible electronic circuits. The p-type doping in ZnO wide band gap semiconductor has been a challenge for research for many years. In this work, Lithium-doped ZnO films were deposited by the RF magnetron sputtering method. The influence of post-annealing temperature on the electrical, structural and optical properties of ZnO:Li films were investigated. The results show that the ZnO:Li films show (0 0 2) preferred orientation and high average transmittance about 85% in the visible region after annealing temperature of about 550 degrees C. The optimal p-type conduction of ZnO:Li film is achieved at the post-annealing temperature of 450 degrees C with a resistivity of 0.22 Omega cm, hole carrier concentration of 2.47 x 10(18) cm(-3) and mobility of 0.22 cm(2)/V s. Finally, p-n homojunction based on transparent semiconducting oxides is fabricated. (C) 2011 Elsevier B.V. All rights reserved.