High-temperature electron emission from diamond films for energy conversion applications

This work examines the electron field emission characteristics of polycrystalline diamond films at elevated temperatures. In recent years, considerable interest has developed in energy conversion applications of polycrystalline diamond films. However, little work has been considered for the field emission characteristics of diamond at elevated temperatures. The motivation behind this study involves direct energy conversion applications in power generation systems, where high temperatures exist. N-doped polycrystalline diamond films were grown by plasma-enhanced chemical-vapor deposition (PECVD). 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 dependency of diamond was achieved through the parameter estimation of the effective emitting area, field enhancement factor, and work function. These results suggest that high-energy electrons are responsible for improved emission at high temperature.