In plasma display panels (PDPs), MgO (magnesium oxide) thin film is used as a protective layer that is placed between the electrodes on the front glass panel on one side of the discharge cells. The aim of this study is to improve the secondary electron emission coefficient of the protective layer. This improvement leads to reduction in consumption of energy. In this study, MgO thin films were prepared using electron beam evaporation method. The ion beam-assisted deposition (IBAD) technique is used to control the crystal orientation, surface nano-morphology, density, and composition. Oxygen ion beam was utilized to irradiate the growing films. In order to control the film properties, the acceleration energy and current density of ion beam and the deposition rate were taken as the variables. The crystallinity, density, composition of the films were analyzed by X-ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS). The secondary electron emission coefficients were measured by an apparatus developed in this study. The experimental results show that the irradiation of ion beam during deposition changes the crystal structure of the films and it influences their secondary electron emission coefficient. (C) 2004 Elsevier B.V. All rights reserved.