Electron field emission from diamond tips prepared by ion sputtering

Abstract

In this letter we report the field emission from cones etched into a synthetic-type IIb (100) oriented boron-doped diamond crystal. The cones were produced with an ion sputtering process. With a high-resolution scanning electron microscope we found the curvature radius at the end of the cones to be less than 10 nm. The length of these cones is in the range of 10 μm giving a field enhancement of approx. 1000. Field emission started at field strength of 2 V/μm, and at 3.8 V/μm 10 nA were measured using a spherical anode of 4 mm diam. From a Fowler-Nordheim fit the work function could be deduced to be 3–4 eV. Hence, electrons are emitted from the valence band.