Controlled synthesis of VO2(R), VO2(B), and V2O3 vanadium-oxide nanowires

Abstract

Vanadium-oxide nanowires (NWs) V2O5, VO2(R), VO2(B), and V2O3 are deposited on a substrate to study their field-emission properties. V2O5 NWs are prepared by thermal evaporation via vapor transport of a vanadium-oxide complex under mild conditions. Films of VO2 and V2O3 wires are subsequently prepared by reducing V2O5 one-dimensional nanocrystals at 450 °C with hydrogen gas. The composition of the flowing H2/Ar mixture and the duration of reduction are utilized to control the formation of VO2(R) or VO2(B) NWs. The crystallinity and morphology of products as prepared are characterized using several techniques, including powder X-ray diffraction, a scanning electron microscope, and a transmission electron microscope. The field-emission properties of the vanadium-oxide NWs as prepared exhibit a turn-on field of 4.56–7.65 V/μm and an emission current density up to 3.68–8.36 mA/cm2. These features indicate that vanadium-oxide NWs have potential FE emitter applications. V2O5, VO2(R), VO2(B), and V2O3 NWs were synthesized via thermal evaporation and controlled reduction process. Field-emission properties of these NWs exhibited turn-on fields of 4–8 V/μm, an emission current density up to 3.5 mA/cm2.