Band model for electron emission from diamond-like carbon and diamond

Electron field emission data from diamond-like carbon and diamond is summarised and a band model is proposed to interpret it. The model is constructed from existing data on electron affinities and band offsets, within a theory of band offsets. In diamond, there is a large offset for the conduction band at the back-contact, causing this to be the dominant tunnel barrier for electron emission. Nitrogen and grain boundaries reduce this barrier by forming a depletion layer of ionised donors, which reduces the tunnelling distance. In diamond-like carbon, the conduction band offset at the back-contact is small and the dominant barrier is at the surface. Nitrogen decreases the emission barrier by increasing the bulk Fermi level and decreasing the work function. (C) 1998 Elsevier Science B.V. All rights reserved.