ZnO:Al (AZO) thin films were deposited on glass substrates by RF magnetron sputtering at room temperature and post-annealed in rapid thermal annealing (RTA) system. The effect of post-annealing temperature on the structural, optical, and electrical properties was investigated. As the post-annealing temperature increased, electrical conductivity is deteriorated due to a decrease in the mobility or carrier concentration, gradually. According to X-ray photoelectron spectroscopy (XPS) analysis, the behavior of mobility and carrier concentration is attributed to increase the O-2 absorption on film surface, which act as rising the barrier potential at the low post-annealing temperature (200 degrees C) and reducing the density of donor-like defects at the high post-annealing temperature (400 degrees C). In case of post-annealing, the minimization of O-2 absorption is a very important factor to obtain better electrical properties. (C) 2013 Elsevier B. V. All rights reserved.