Thermionic FEEM, PEEM and I/V Measurements of N-Doped CVD Diamond Surfaces
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Thermionic FEEM, PEEM and I/V Measurements of N-Doped CVD Diamond Surfaces F.A.M.Köck, J.M. Garguilo, B. Brown, R.J. Nemanich Department of Physics North Carolina State University Raleigh, NC 27695-8202 USA Abstract Imaging of field emission and photoemission from diamond surfaces is accomplished with a high resolution photo-electron emission microscope (PEEM). Measurements obtained as a function of sample temperature up to 1000ºC display thermionic field emission images (TFEEM). The system can also record the emission current versus applied voltage. N-doped diamond films have been produced by MPCVD with a N/C gas phase ratio of 48. The surfaces display uniform emission in PEEM at all temperatures. No FEEM images are detectable below 500ºC. At ~680ºC the T-FEEM and PEEM images are nearly identical in intensity and uniformity. This is to be contrasted with other carbon based cold cathodes in which the emission is observed from only a low density of highly emitting sites. The I/V measurements obtained from the N-doped films in the T-FEEM configuration show a component that depends linearly on voltage at low fields. At higher fields, an approximately exponential dependence is observed. At low temperatures employed (
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