A simple SVS method for obtaining large-scale WO3 nanowire cold cathode emitters at atmospheric pressure and low temperature

Abstract

Large-scale WO₃ nanowire patterns have been successfully fabricated on a 3.5 inch glass substrate at atmospheric pressure by a simple no-catalyst method. The nanowires were observed to have a mean length of about 40 μm, and their aspect ratio reaches 200. The nanowires were proven to be single crystalline WO₃ with a monoclinic structure. It is found that the growth region and growth density of the WO₃ nanowires differ with the interval or the width of the W stripes. By combination of designing a series of experiments and analyzing the growth kinetics theory, a novel self-supported vapor–solid (SVS) mechanism is proposed to be responsible for the formation of WO₃ nanowires. Field emission (FE) measurements show that the WO₃ nanowire patterns have excellent FE performance, which have a low turn-on field of 2.9 V μm⁻¹ and good field emission uniformity of over 85%. Moreover, this SVS method may provide a helpful reference on low-temperature and no-catalyst growth of other metal oxide nanostructure arrays at atmospheric pressure.