Efficient electron emitter utilizing boron-doped diamond tips with sp2 content

A practical technique to enhance the electron emission of diamond tips by incorporation of boron dopant and sp(2) content is reported. The effects of boron doping on electron field emission from an array of micro-patterned polycrystalline pyramidal diamond microtips with varying sp(2) content have been systematically studied. The field emission characteristics of undoped and boron-doped diamond tips are significantly improved by increasing sp(2) content of diamond tips. By increasing sp(2) content, the turn-on electric field can be reduced more than 50% for both undoped and boron-doped diamond tips. Likewise, the turn-on electric field of the diamond tips with higher sp(2) content decreases substantially with boron doping. A new field emission mechanism, that is, an increase in the field enhancement factor due to hole accumulation via the formation of cascaded sp(2)-diamond-sp(2) embedded microstructures in diamond tips, is a possible explanation for the enhanced effects of boron doping and sp(2) content on the diamond field emission characteristics, (C) 1999 Elsevier Science B.V. All rights reserved.