Nanotips exhibit a low turn-on field and high emission current density, which are considered as promising candidates in future cold field emitters. However, it’s difficult to fabricate emitter with ultra-fine curvature radius, outstanding collimation and stable interfacial adhesion. In this study, we developed an in-situ technique that enables the fabrication of single-crystal hafnium carbide (HfC) nanotips on top of tungsten (W). The single-crystal feature and outstanding collimation of HfC nanotips were confirmed using transmission electron microscopy (TEM). The in-situ TEM investigation revealed that the HfC nanotip exhibited a typical field emission turn-on voltage of 128 V (20 nA), and a significant current of ~230 nA at a low extraction voltage of 149 V, when the distance between the tip and extractor is ~50 nm. The field enhancement factor of the HfC nanotip was as high as ~2×107 m-1. The exceptional properties can be attributed to the single-crystal feature, the nanometer-sized apex, the outstanding collimation and the stable interfacial adhesion of HfC nanotip.
