Synthesis and field emission of single-crystalline copper vanadate nanobelts

Single-crystalline nanobelts of a nonstoichiometric compound Cu1.55V2O6.55, with a thickness of 40-60 nm, width of 50-300 nm and length of several micrometers, have been synthesized on a large scale by a hydrothermal method. The structures and morphologies of the nanobelts were characterized by x-ray powder diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. A probable growth mechanism has also been discussed. The nanobelts exhibit a turn-on field of 11.0 V mu m(-1), which is defined as the macroscopic field required to produce a current density of 10 mu A cm(-2). It is anticipated that the nanobelts can serve as a candidate material for future field emitters.