Field Emission Properties of Vertically-Aligned Carbon Nanotubes Grown on Stainless Steel by Hot-Filament Chemical Vapor Deposition

Abstract

Carbon nanotubes (CNTs) for field emission applications were grown directly on 304 stainless steel (SS304) by using hot-filament chemical vapour deposition (hot-filament CVD). Vertically-aligned CNTs (VACNTs) with 1.5-millimetre-diameter in shape were successfully grown on the SS304 substrate. We obtained efficient electron emission with turn-on fields as low as 0.66 V/µm, emitting currents of 1.5 mA at an applied field of about 1.5 V/µm. The VACNTs-SS304 emitter also demonstrated high stability in emission current of 860 µA (« 12.5 µA) which even better than that of the VACNTs grown on conventional silicon. This VACNTs-stainless steel is a promising candidate for X-ray tubes that require small, bright, and cold emitters.