Stable Electron Emission from Graphite-Nanoneedles and Their Application to Scanning Electron Microscopes

The authors demonstrate both the stable and high brightness field emission from graphite nanoneedle (GRANN) cathode fabricated by simple plasma etching of a graphite rod. Bright electron emission of the order of 10¹² Asr^-1m^-2) is obtained from GRANN cathode. As well as the bright emission, a stable emission under high residual pressure (10^-5 torr) is obtained by lightly heating the GRANN cathode (Thermal-FE operation). The performance of the GRANN cathode is demonstrated by the construction of an FE scanning electron microscope (SEM) with the GRANN cathode and clear FE-SEM images are obtained at high residual pressure of the order of 10^-5 torr