Low temperature growth of vanadium pentoxide nanomaterials by chemical vapour deposition using VO(acac)₂as precursor

Abstract

Vanadium pentoxide (V2O5) nanomaterials with various morphologies were prepared by chemical vapour deposition at a relatively low temperature (evaporation temperature of 250 degrees C and growth temperature of 500 degrees C) using vanadyl acetylacetonate (VO(acac)(2)) powder as the vanadium precursor. The obtained samples were characterized by scanning electron microscopy, x-ray diffraction, Raman scattering and photoluminescence spectra. The results revealed that the samples including a V2O5 nanocluster film, V2O5 nanowires and V2O5 nanospheres were synthesized at different distances from the source material. For our chemical vapour transport system, we suggested that VOx vapour and VO(acac)(2) vapour existed simultaneously during the growth process, which resulted in different morphologies of V2O5 nanomaterials. The quite different supersaturation distributions of VOx vapour and VO(acac)(2) vapour led to three main growth areas. The V2O5 film was grown in the region where the supersaturation of the VOx vapour was high, V2O5 nanowires were obtained where the supersaturation of the VOx vapour was relatively low and V2O5 nanospheres were synthesized in the region where the supersaturation of the VO(acac)(2) vapour was high. The growth pressure that influenced the vapour concentration controlled the morphologies of the nanowires. It was found that a specific level of low concentration was necessary to ensure the growth of V2O5 nanowires.