In this investigation, a novel technique was applied to MgO films for the purpose of improving the secondary electron emission coefficient. It is believed that a high secondary electron emission coefficient of an MgO protective layer could lead to a high performance of a plasma display panel. An oxygen ion beam irradiation was employed at varying modification time. Characterization of the modified MgO surface was performed using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The secondary electron emission coefficient of MgO films was measured using a newly developed apparatus. It was observed that the oxygen ion irradiation increased the secondary electron emission coefficient of MgO films. A significant increase was observed for the MgO films with low ion irradiation time. Results obtained from XPS and AFM suggested that the secondary electron emission coefficient of MgO films was considerably dependent on the surface nano-morphology. High secondary electron emission coefficient was observed for MgO films with a smooth surface. (C) 2003 Elsevier B.V. All rights reserved.