In-situ Fourier transform infrared spectroscopy gas phase studies of vanadium (IV) oxide coating by atmospheric pressure chemical vapour deposition using vanadyl (IV) acetylacetonate

This paper describes the use of in-situ Fourier transform infrared spectroscopy to monitor the gas phase reactions of the formation of VO₂ thin films from VO(acac)₂ under atmospheric pressure chemical vapour deposition conditions. In the absence of O₂, it is found that anhydride species may form, while there is also some evidence of ester species. In the presence of O₂, the spectra obtained are almost identical to those in the absence of O₂. However in this case, there is also some indication for the enhanced production of CO and the suppression of the formation of C-H species. A possible mechanism for the formation of VO₂ is proposed, which involves the release of two C₃H₄ molecules and the decomposition of vanadyl (IV) acetylacetonate into VO(CH₃COO)₂, which then further decomposes to yield (CH₃CO)₂O and VO₂. However, while spectroscopic evidence for the formation of these species is presented, the mechanism proposed cannot be confirmed on the basis of these data alone.