Pulsed Laser Deposition of Diamond-Like Carbon Films on Gated Si Field Emitter Arrays for Improved Electron Emission

Abstract

Diamond-like carbon (DLC) films were deposited on niobium gated silicon field emitter arrays to improve the emission properties. DLC deposition was carried out either ex-situ by con-ventional pulsed laser deposition in a separate chamber or in-situ during electron emission in a test chamber. Various process parameters such as the thickness of the DLC films and the ambient gas during film deposition were systematically varied. The thickness of the DLC coating was found to play a crucial role for the emission characteristics of the FEA. An increase of both the emission current and its stability could be achieved using thin DLC films up to 6 nm. Thicker films, on the other hand, caused a decrease in the emission current. The results could be explained by a metal-insulator-metal (MIM) model for the electron transport through the DLC film. An increase or decrease of the emission current was observed also for the in-situ deposited DLC films depending on the gas environment during the deposition process.