Secondary electron emission performance of the surface Ni-doped MgO-Au thin film under continuous electron bombardment

[Display omitted] •A surface Ni-doped MgO-Au thin film was prepared by magnetron sputtering.•Surface Ni-doping resulted in a reduction of MgO particle size and MgO bandgap.•Electrical conductivity of MgO-Au film was improved by surface Ni-doping.•Surface Ni-doping effectively suppressed the secondary electron emission decay. A surface Ni-doped MgO-Au thin film was prepared by reactive magnetron sputtering and showed a superior secondary electron emission (SEE) performance under continuous electron bombardment in comparison with an undoped one. The experimental results show that the surface Ni-doping improves the electrical conductivity of MgO-Au film due to a size reduction of MgO particles and a bandgap narrowing of the surface MgO layer. Additionally, a 3.4 at% Ni-doped MgO-Au film exhibits an average SEE decay rate per hour as low as 2.6% with a reduction of 31.6% under continuous electron bombardment compared with the undoped one, and especially its SEE coefficient turns to be higher after 4-hour electron bombardment. Thus, the surface Ni-doping is an effective strategy to suppress the surface charging effect and subsequent SEE decay of MgO-Au film owing to the improvement of electrical conductivity.