Li-doped, p-type ZnO thin films have been realized via dc reactive magnetron sputtering. An optimized result with a resistivity of 16.4 Omega cm, Hall mobility of 2.65 cm(2)/V s, and hole concentration of 1.44x10(17) cm(-3) was achieved, and electrically stable over a month. Hall-effect measurements supported by secondary ion mass spectroscopy indicated that the substrate temperature played a key role in optimizing the p-type conduction of Li-doped ZnO thin films. Furthermore, ZnO-based p-n homojunction was fabricated by deposition of a Li-doped p-type ZnO layer on an Al-doped n-type ZnO layer. (c) 2006 American Institute of Physics.