Theory and Experimental Results of a New Diamond Surface-Emission Cathode

VOLUME 10, NUMBER 1, 1997 THE LINCOLN LABORATORY JOURNAL 3 D  - cathodes show great promise for use in flat-panel displays, fluorescent lighting, and power vacuum tubes that switch thousands of amperes. Unlike metal-emission cathodes, diamond surface-emission cathodes can operate at low voltages and would be easy and inexpensive to fabricate. Although many research groups have reported emission from diamond and amorphous diamond-like films at electric fields on the order of a megavolt per meter, the use of these materials as cathodes is limited by their unreliable performance [1, 2]. Researchers generally attribute the unreliable performance to inconsistent bulk properties of the diamond cathode material, which is believed to cause electron emission from only a small number of spatially localized sites. We have found a surface-emission mechanism that may help explain nonuniform emission in diamond: enhanced electron emission at the triple-junction interface of a diamond surface, a conductive region, and a vacuum. Our research suggests that a discontinuous diamond film with an abundance of these interfaces could be a better electron emitter than the conventional approach of a continuous diamond film. Theory and Experimental Results of a New Diamond Surface-Emission Cathode