Field emission from wide band gap materials

Summary form only given. It has been reported that diamond and amorphous diamond materials possess excellent properties as coatings for electron emitters. After coating the emission current increased by several orders of magnitude compared to the same uncoated emitter, although the reasons are not entirely clear. It has been reported that a current density of 10/sup 3/ A/cm/sup 2/ can be drawn for a field of 40 V//spl mu/m from a single crystal p-type or n-type diamond. For polycrystalline diamond films with no doping, the required field is only 3 V//spl mu/m to achieve such a current density. Very high current densities have been reported at extremely low "turn on" voltages, with excellent current stability. In this presentation, experimental data on the emission behavior of field emitters coated with diamond, AlN, amorphous diamond, and nitrogen doped CVD diamond will be presented. A proposed general mechanism of electron emission from wide band gap materials will be discussed based on experimental data from energy analysis, microstructural analysis, and field emission characterization following different surface treatments.