Na-diffused p-type ZnO thin films were realized via pulsed laser deposition using NaF ceramic target followed by rapid thermal process in nitrogen. An optimized result with a resistivity of 426.7Ωcm, a Hall mobility of 7.54cm2/Vs, and a hole concentration of 1.94 x 1015/cm3 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.

Effects of Diffusion Temperature and Diffusion Time on Fabrication of Na-Diffused p-Type ZnO Thin Films. Liu, H., Pan, X., Ding, P., Ye, Z., He, H., Huang, J.: Materials Letters, 2012, 80, 175-7