Negative Electron Affinity On Polycrystalline Diamond Surface Induced By Lithium Fluoride Deposition

Lithium fluoride (LiF) was deposited on hydrogenated and oxygenated polycrystalline diamond surfaces. Lowering of the work function induced by the dipole effect of LiF was clearly observed using UV photoemission spectroscopy and Kelvin probe. The decrease of the work function was sufficiently large so that negative electron affinity was induced. This shows that the LIF overlayer on diamond acts as an effective dipole layer to lower the surface work function of the diamond film. (C) 1999 Elsevier Science S.A. All rights reserved.