Effects of diffusion temperature and diffusion time on fabrication of Na-diffused p-type ZnO thin films

Na-diffused p-type ZnO thin films have been realized via pulsed laser deposition using NaF ceramic target followed by rapid thermal process in nitrogen. An optimized result with a resistivity of 426.7 Omega cm, a Hall mobility of 7.54 cm(2)/Vs, and a hole concentration of 1.94 x 10(15) cm(-3) was achieved, and the films were electrically stable over several months. Hall-effect measurements supported by X-ray photoelectron spectroscopy indicated that diffusion temperature and diffusion time played a key role in optimizing the p-type conduction of Na-diffused ZnO thin films. Furthermore, ZnO-based p-n homojunction was obtained by fabrication of a Na-diffused p-type ZnO layer on an undoped n-type ZnO layer. (C) 2012 Elsevier B.V. All rights reserved.