Abstract
An investigation has been made on the hydrolysis behavior of vanadyl isopropoxide, VO(O-i-C3H7)3, in which a wide range of hydrolysis water content (0<r (=[H2O]/[VO(O-i-C3H7)3])<500; in molar ratio) and alkoxide concentration (0<q (=[VO(O-i-C3H7)3]/[i-C3H7OH])<0.08) were used to be examined. It has been found that there exists a viscous solution phase in a rather high water content region; r>200, along with its known phases of liquid, precipitate and gel below this level of water content. All the phases of precipitate, gel and viscous sol in the VO(O-i-C3H7)3-H2O-i-C3H7OH system were confirmed by X-ray diffraction analysis to contain primary particles with nearly the same crystal structure. Using a precursor solution (unhydrolyzed) and a viscous sol solution of VO(O-i-C3H7)3, thin films of vanadium oxide were prepared on SiO2/Si substrates by spin coating, followed by firing at 450°C in air. A comparison has been made between the two vanadium oxide films obtained in terms of their surface morphologies, and it has been confirmed that the viscous solutions have an advantage over the precursor solution in using as a coating solution for producing vanadium oxide thin films of good quality.
