In this paper, we studied the variation of surface properties of N+ ions-implanted ZnO films. The ZnO films deposited on K9 glass substrate by direct current reactive magnetron sputtering were firstly implanted with N+ ions and subsequently subjected to process by rapid thermal annealing (RTA) in N-2 ambience. The crystallographic properties and surface morphology were examined by X-ray diffraction and atomic force microscopy, respectively. The implantation of N+ ions and RTA not only roughens the surface of ZnO films but also changes the conduction type from the n-type to weak p-type. The resistivity of ZnO films was measured by the four-point probe method and the variation of the conduction type was observed by cool-hot probe point. The resistivity of ZnO films subjected to RTA at 500 similar to 600 degrees C decreased about 6-9 orders of magnitude. The optical properties have no significant change. (c) 2005 Elsevier B.V. All rights reserved.