High-temperature electron emission from diamond films

S. H. Shin, Department of Mechanical Engineering, Vanderbilt University
Timothy Fisher, School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University
D. G. Walker, Department of Mechanical Engineering, Vanderbilt University
A. M. Strauss, Department of Mechanical Engineering, Vanderbilt University
W. P. Kang, Department of Electrical Engineering and Computer Science, Vanderbilt University
J. L. Davidson, Department of Electrical Engineering and Computer Science, Vanderbilt University

Abstract

This work examines electron field-emission characteristics of polycrystalline diamond films at elevated temperatures. Diamond is an excellent material as a field emitter because of its exceptional mechanical hardness and chemical inertness. The motivation behind this study involves the use of field emitters in applications where high temperatures exist. Nitrogen-doped polycrystalline diamond films were grown by plasma-enhanced chemical-vapor deposition. To investigate the effect of increased temperatures on field emission, current–voltage measurements were taken from the same diamond film at varying temperatures. Results from these measurements indicate a decrease in the turn-on voltage with increasing temperature. Further analysis of the temperature dependence of emission is achieved through parameter estimation of the effective emitting area, field enhancement factor, and work function. These results suggest that thermally excited electrons are responsible for improved emission at high temperature.