Growth of nanowires of β-NaxV2O5 by metalorganic chemical vapor deposition

Abstract

Films comprised of nanowires of β-Na_xV₂O₅ measuring 20–200 nm in diameter and 10–30 µm in length have been prepared on glass substrates by metalorganic chemical vapor deposition using the β-diketonate complex, vanadyl acetyl acetonate, as precursor, but without the use of either templates or catalysts. Films consisting of nanowires of monophasic β-Na_xV₂O₅ with a preferred orientation along (h0l) are formed only at 550 °C, whereas those deposited at 540 °C comprise a mixture of nanowires (β-Na_xV₂O₅) and platelets (V₂O₅). The films deposited at lower temperatures are less crystalline and comprise a mixture of vanadium oxide phases. From the observations that nanowires are formed only in the narrow temperature range of 540–550 °C, and from the critical dependence of the formation of nanowires on the balance between the CVD growth rate and the evaporation rate of the film, it is inferred that the formation of nanowires of β-Na_xV₂O₅ is due to chemical vapor transport.