Effect of Firing Temperature on the Structural, Optical, and Electrical Properties of VO2 Thin Films Deposited by Chemical Solution Deposition

Characteristics of VO2 fi lms prepared on alkali-free glass substrates by chemical solution deposition (CSD) using vanadyl oxalate nhydrate as the raw material are investigated. Diffraction peaks corresponding to VO2 are observed in the samples obtained at fi ring temperatures of 350 to 550 degrees C. However, diffraction peaks of the samples obtained at 500 and 550 degrees C show a mixture of VO2 and V 6 O 13 phases. Regarding the surface and cross-section morphology of the fi lms, the crystal grain size and porosity of the fi lms steadily increase with fi ring temperature. The samples show an abrupt change in resistivity around 70 degrees C. The change in resistivity caused by the metal-insulator transition are about three orders of magnitude. The sample transmittance in the near-infrared region decreases sharply with the phase transition. The maximum reduction in transmittance at 2000 nm is 55.4%.