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

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.