Smooth, uniform and crystalline vanadium oxide thin films were deposited on quartz by spin coating technique
with four different rpm i.e., 1000, 2000, 3000 and 4000 and subsequently post annealed at 350, 450 and 550 °C
in vacuum. Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM) and
X-ray diffraction (XRD) techniques were utilized for microstructural characterizations and phase analysis, respectively,
for vanadium oxide powder and deposited film. Nanorods were observed to be grown after vacuum
annealing. X-ray photoelectron spectroscopy (XPS) technique was utilized to study the elemental oxidation state
of deposited vanadium oxide films. Thermo-optical and electrical properties such as solar transmittance (τs),
reflectance (ρs), absorptance (αs), infrared (IR) emittance (εir) and sheet resistance (Rs) of different thin films
were evaluated. Based on the optical characteristics the optimized condition of the film processing was identified
to be spin coated at 3000 rpm. Subsequently, the nanoindentation technique was utilized to measure hardness
and Young's modulus of the optimized film. The measured nanomechanical properties were found to be superior
to those reported for sputtered vanadium oxide films. Finally, temperature dependent phase transition characteristics
of optimized vanadium oxide films were studied by differential scanning calorimetry (DSC) technique.
Reversible and repeatable phase transition was found to occur in the range of 44–48 °C which was significantly
lower than the phase transition temperature (i.e., 68 °C) of bulk VO2