AND TABAT Theory and Experimental Results of a New Diamond Surface-Emission Cathode nikolay n. efremow, jr. is an assistant staff member in the Submicrometer Technology group, where he fabricates and characterizes diamond emitters for flat-panel displays.

Abstract

■ A new electron-emission mechanism combines the enhanced electric field of a triple junction at the intersection of metal and diamond interfaces in vacuum with the negative electron affinity (NEA) of the diamond surface. This new surface-emission mechanism is compared to two common cathode mechanisms—geometric electric-field enhancement and Schottky-diode electricfield enhancement with an NEA semiconductor. Unlike these two mechanisms, in which electrons tunnel from metal into vacuum or into the conduction band of an NEA semiconductor, in our mechanism electrons tunnel from metal into surface states at the interface of an NEA semiconductor and a vacuum. Once in these states, the electrons are accelerated to sufficient energies to be emitted from the surface into vacuum. New cathodes designed to maximize the surface-emission mechanism exhibit improved consistency and reduced operating voltage when compared to cathodes that use other mechanisms. Gated surface-emission cathodes emit measurable current densities greater than 10 –6 A m –2 at gate voltages of 3 to 4 V