High-efficiency secondary-electron emission from sputtered MgO–Au cermets

We have obtained high-efficiency secondary-electron emission from a new sputtered cermet system, MgO–Au. Peak yields of 8 and quantum gain for primary-electron energies as low as 17 eV have been achieved on thick films without the presence of surface charging. The very small insulator particle sizes (< 50 Å) in the films permit removal of surface charge by tunneling to adjacent metallic regions. This type of emitter is potentially useful for secondary-emitting cathodes in high-power device applications as well as low-power electron multiplication.