Phase transformation of diamond ®lms during electron ®eld emission

Polycrystalline diamond ®lms consisting of submicron grains show ef®cient electron ®eld emission properties, i.e. low emission threshold ®elds, high emission current and emission luminescent spot densities on indium tin oxide (ITO) coated glass anodes. After emission, we examined the emission sites on the surfaces of diamond crystals. Some micron-sized diamond crystals transformed into nanoparticle diamond, amorphous carbon, and graphite phases, as detected by micro- Raman spectroscopy in the local emission areas of the diamond ®lms. The experiments indicate that nanoparticle diamond ®lms with high sp2 carbon phase content may be an ef®cient and stable cathode material for ®eld emission display application. # 2001 Elsevier Science B.V. All rights reserved