Preliminary design and experimental evaluation of carbide field emitters in mTorr pressure environments

Summary form only given. This report describes an on-going effort to develop field emitter cathodes for mTorr-level discharges. Hafnium carbide and zirconium carbide emitters were used for their hardness, chemical inertness and low work functions. Single HfC emitters were tested in oxygen at mTorr pressures. They showed resistance to damage due to backsputtering even at relatively large extraction voltages. Emitter-gate electrode configurations were then optimized for mTorr pressure environments to prevent catastrophic failure of the arrays from arcing. The results of the design analysis, emission measurements under various gases and pressures, and experimental evaluations of the design are presented in this report.