Vapor-Solid Growth of Molybdenum Oxide Nanowhiskers: Wettability Studies and Growth Process

摘要

MoO_2 coatings were grown on silicon substrates using vapor-solid mechanism at different filament temperatures, durations and oxygen flow rates. The coating deposited at a filament temperature of 1500℃ with oxygen flow rate in the range of 4-8 sccm exhibited nanowhisker microstructure. The wettability studies indicated that the as-prepared MoO_2 coating is hydrophilic in nature whereas, MoO_2 coating treated with silane showed a high contact angle of 156°. The nanoscale protrusions combined with low surface free energy silane coating resulted in superhydrophobicity. The growth sequence of MoO_2 nanowhiskers was studied in detail using field emission scanning electron microscopy. X-ray photoelectron spectroscopy and micro-Raman spectroscopy studies confirmed the presence of MoO_2 in the as-deposited coating. The changes in the structures of the MoO_2 coatings with respect to the growth conditions were studied using X-ray diffraction.