Secondary electron emission enhancement of MgO/Au composite film by adopting a gold buffer layer

An electron-induced secondary electron emission (SEE) enhancement strategy of depositing a gold buffer layer for MgO/Au composite film was proposed. The influence of the gold buffer layer thickness on the microstructure, electrical conductivity and SEE properties of MgO/Au film was investigated. To deposit a gold buffer layer between the substrate and MgO/Au composite film markedly promotes the subsequent MgO grain growth, which leads to an increase in the SEE coefficient. Additionally, the improved electrical conductivity of this composite film caused by the gold buffer layer can effectively suppress the surface charging, which makes the MgO/Au film maintain a higher SEE coefficient for a longer time under continuous electron bombardment. An MgO/Au composite film with a 20-nm-thick gold buffer layer has a SEE coefficient of 5.1 at a primary electron energy of 200 eV with an increase of 13.3% compared with the one without a gold buffer layer.