Thermionic Electron Emission from Ultrananocrystalline Diamond Films

Abstract

In this work, we synthesized CH₄/Ar-based ultrananocrystalline diamond (UNCD) films by using a microwave plasma enhanced chemical vapor deposition method. These films exhibit improved thermionic electron emission (TEE) properties with a work function value of 4.8 eV and a high current density of 0.47 mA/cm². The high field enhancement factor and the amorphous carbon phases at the grain boundaries of UNCD films are the reliable features for the improved TEE characteristics of UNCD films. The results encourage the potential use of UNCD films for efficient thermionic electronic emission devices.