Field emission from diamond needles produced by CVD growth

Polycrystalline CVD diamond films were thermally oxidized in order to obtain single-crystal diamond needles. Field electron emission properties of the needles were studied using UHV system equipped with an electron energy analyzer. Current-voltage characteristics have shown strong current saturation that is predicted by the basic theory of the electron emission from semiconductors. Using the energy analyzer total energy distributions of the emitted electrons were measured as a function of temperature and current. This permitted estimation of activation energy of the saturation current and definition of possible mechanisms of carrier transport. Obtained results show that despite the large band gap of diamond, the needles obtained by thermal oxidation of polycrystalline CVD diamond films without intentional doping can be used as effective field emission point sources.