Samples with various defect densities were prepared by chemical vapor deposition, and their field emission characteristics were investigated. Vacuum electron field emission measurements indicated that the threshold electric field which was required in order to generate more than 10mA/cm2 could be significantly reduced if the material was prepared so as to contain a large number of structural defects. Such material exhibited a Raman spectrum with a broadened peak at 1332/cm, with a full-width at half-maximum of between 7 and 11/cm. It was established that there was a strong correlation between the field which was required for emission, and the full-width at half-maximum of the diamond peak. The threshold fields were typically less than 50V/, and could be as low as 30V/ for samples with a full-width at half-maximum that was greater than 8.5/cm. It was suggested that the defects created additional energy bands within the band-gap, and thus contributed electrons for emission at low electric fields.

W.Zhu, G.P.Kochanski, S.Jin, L.Seibles: Journal of Applied Physics, 1995, 78[4], 2707-11