Field emission enhancement achieved by selective multi-walled carbon nanotubes deposition over silicon microstructures

Field Emission (FE) devices have been studied due to their attractive characteristics: they are cold cathode electron emitters, and can be used as ionization sources for several applications. However, miniaturization, emission efficiency, and integration with electronic circuits are aspects that need to be enhanced. This paper reports silicon (Si) FE devices successfully optimized by the combination of miniaturized structures and multi-walled carbon nanotubes (MWCNT). MWCNT were deposited over Si microtip arrays by electrophoretic deposition (EPD), and a selective coating without additional lithographic masks was achieved with appropriate process parameters. Our devices were electrically analyzed by means of macroscopic electric field (E), which demonstrated to be efficient for experimental performance comparison among samples. FE devices covered with CNT showed an E reduction up to 80% for a given current, which indicates a considerable enhancement in electron emission efficiency. We conclude that the appropriate combination of microstructures and CNT deposition parameters is suitable for the development of efficient and cost-effective integrated FE devices.