Synthesis of vanadium pentoxide (V2O5) nanobelts with high coverage using plasma assisted PVD approach

Cost-saving, easy-handling, and eco-affable plasma assisted sublimation process (PASP) is proposed to synthesize vanadium pentoxide (V2O5) nanobelts (NBs) with excellent coverage on Si [1 0 0] wafer using oxygen plasma without using surfactants/catalysts. Pure orthorhombic V2O5 NBs having average length of few hundred of microns with quite uniform width nearly of 100 nm are formed at 500 °C. No film is deposited on Si in presence of oxygen gas without exciting plasma at 500 °C. HRTEM analysis with SAED pattern confirm that all V2O5 NBs are single crystalline in nature with the fringe width of 0.33 nm corresponding to [0 1 0] crystal plane. The XPS analysis shows the compositional purity and sub-stoichiometric nature of V2O5 NBs. The sub-stoichiometric nature of NBs is manifested through an appearance of low intensity peak corresponding to low oxidation state of V (i.e. V4+) at the binding energy of 514.8 eV. The micro-Raman and FTIR analysis of NBs are carried out to study the different vibrational modes exhibited by V and O atoms coordinated in distinct fashions. The nanobelts exhibit room temperature PL emission in UV-visible realm with a broad hump in the range of 450-750 nm, which confirms the presence of oxygen defects in NBs and strongly supports the XPS results as well. The possible growth mechanism of α-V2O5 NBs is proposed in this paper briefly.