Electron-field emission measurements from boron-doped CVD diamond on tantalum

Boron-doped polycrystaline diamond films grown by hot-filament-assisted chemical vapor deposition were studied with ultraviolet photoemission spectroscopy (UPS), Raman spectroscopy, X-ray diffractometry and current voltage measurements. The UPS measurement shows that the work function (0) without electric field is about 3.9 W. The field-emission current-voltage measurements indicate a threshold voltage ranging from 8.97x10(6) to 9.64x10(6) V/m and a work function (phi) about.0.3 eV. These results show that boron doped diamond films exhibit a negative electron affinity in high electric field.