Preparation of MgO/Au Multilayer Composite Films and Related Studies on Secondary Electron Emission Effect

MgO thin film has a high secondary electron emission coefficient. However, the accumulation of electric charge on the surface of the thin film will inhibit it. This paper mainly discusses this phenomenon with the method of reactive magnetron sputtering. We prepared a MgO/Au buffer layer by co-sputtering Au in the inner layer of MgO. The experiments show that Au distributes mainly in the gap of the MgO grains. Adding appropriate Au will promote the growth of MgO grains in the longitudinal direction, increase the conductivity of the material, suppress the accumulation of electric charge on the surface, and increase the secondary electron emission coefficient of the thin film. NiO was also used as the transition layer of MgO and substrate in the experiments, so as to increase the adhesion of the MgO films and improve the quality of the thin film. According to the experiment results, the maximum secondary electron emission coefficient of MgOAu multilayer composite film increased by 28.9% compared with that of the pure MgO film. Under the continuous irradiation of 200 eV incoming energy, the decay rate decreased from 35.2% to 30.6% in 1 h.