Nitrogen-doped nanodiamond films grown just by heating solid precursor thin layers for field emission application

Nanodiamond films with nanoscale grain sizes are highly desired for versatile applications, such as sensors and field emitters, due to their special physical and chemical properties. In this paper, a simple, safe, green and cost-effective approach for growing intrinsic and nitrogen (N)-doped nanodiamond films just by heating the solid thin layers of glucose and/or urea on nickel-coated stainless steel in a resistance-heating furnace is reported. The N doping concentration of 0 to 2.63 at.% can be adjusted by the urea addition in the precursors. Moreover, this method can be easily extended to other organic carbon and dopant sources. Measurement of the field electron emission properties indicates that stable emission with a low turn-on electric field strength of 3.6 V µm−1 defined at the current density of 0.01 mA cm−2 can be delivered for the N-doped nanodiamond film grown from the precursor thin layer of glucose + urea (1:1 in mass).