Electron Emission from Nano-Structured Diamond Films Deposited on Ion Implanted Si Substrates

Electron emission from diamond surface can occur due to its low or even negative electron affinities. Diamond films can show a planar electron emission property at low electric field and be manufactured cheaply. Although a considerable research effort on diamond field emission has been made in decade, there are no obvious mechanisms by which electrons can be transported through the bulk diamond film to the surface and how to obtain stable electron emission. Nano-structured diamond film is one of the most promising materials for active display device because the high grain boundary density in film can submit more emit sites. In this paper we reported that the enhanced and stable electron emission at low applied fields is obtained from nano-structured diamond films deposited on Si substrates implanted by high concentration boron (B) and phosphor (P) ion. 3 micron-thickness nano-structured diamond films were grown on B and P ion implanted Si wafers by a microwave plasma enhanced chemical vapor deposition (MPECVD) process. The average grain size for films deposited on high concentration B and P implanted substrates is 30-200 nm. The electron emission properties from the films on implanted substrates were studies, an enhanced emission property from high concentration implanted samples were concluded. The results show that the high concentration implanted samples have an obvious decreasing in threshold and increasing in current density, particular to the high concentration P implanted sample. This can be attributed to the higher grain boundary density induced by small grain size of nano-structured diamond films deposited on implanted substrates, which permit more emit sites.