Secondary electron emission of B-doped/undoped double-layer heteroepitaxial single crystal diamond film

Abstract

A B-doped/undoped double-layer single crystal diamond structure was proposed to enhance secondary electron emission (SEE), and the double-layer single crystal diamond film was heteroepitaxially grown on MgO substrate by microwave plasma chemical vapor deposition. The crystal quality, surface morphology and conductivity of the film were studied. It is found that the film has high crystal quality, the full width at half maximum of X-ray diffraction rocking curve is 0.14°, and the surface roughness is small. For these reasons, the B-doped/undoped double-layer single crystal diamond film has better SEE performance than the B-doped/undoped double-layer polycrystalline diamond film. At the incident electron energy of 2 keV, the SEE yield of B-doped/undoped double-layer single crystal diamond reached 22.4. The physical model calculation results indicate that at a low B doping concentration, less sp2 carbon and smaller surface roughness are beneficial to improve the SEE yield.