Controlled growth of β-Na0.24V2O5 nanowire thin films

A method to prepare well-aligned β-Na0.24V2O5 nanowires (NWs) involves the deposition of a vanadium oxide complex onto a substrate via gaseous transport, followed by a reaction between the complex and a sodium cation (Na+) precursor coated on the substrate. Techniques to investigate the composition, crystallinity, and morphology of products as prepared include ICP-AES, X-ray powder diffraction (PXRD), SEM/transmission electron microscope (TEM), and XPS. PXRD patterns and images from a TEM confirm the single-crystalline nature of β-Na0.24V2O5 NWs, which grow along direction [1 0 0]. Factors affecting the amount of deposited material and morphology were tested. On varying the reaction conditions, the length of the β-Na0.24V2O5 wires is controlled in a range of 5–25 μm. A mechanism of formation is proposed. According to measurements of field emission, the turn-on field is 7.8 V/μm, and the maximum emission current density of 4.66 mA/cm2 occurs at field 11 V/μm. This method is applicable to grow other tertiary metal oxide nanostructures on glass substrate.Graphical abstractAligned β-Na0.24V2O5 nanowire thin film was prepared via a novel procedure of thermal deposition. The length of the nanowires was controlled by adjusting the reaction temperature and the concentrations of reactants. Measurements of the field emission exhibited excellent properties with a linear Fowler–Nordheim behavior.