Luminous transmittance and phase transition temperature of VO₂:Ce thin films prepared by DC reactive magnetron sputtering

Abstract

Vanadium dioxide (VO₂) and cerium-doped vanadium dioxide (VO₂:Ce) thin films were prepared by DC reactive magnetron sputtering from vanadium metallic target and V-Ce alloy targets. Luminous transmittance and phase transition temperatures of the films were studied. The Shimadzu SOLIDSPEC-3700 DUV-VIS-NIR spectrophotometer was used to measure the transmittance and reflectance of the films. The phase transition temperature (τ_c) of the films was obtained from both the transmittance and sheet resistance against temperature curves. A change in sheet resistance of 2 to 3 orders of magnitude was observed for both undoped and Ce-doped VO₂ films. Comparison between undoped and doped VO₂ films revealed that cerium inclusion altered both the visible and infrared transmittance of VO₂ thin films. Luminous transmittance was slightly enhanced while τ_c was slightly depressed by cerium inclusion in VO₂. A two-step increase in transmittance observed in the cooling loop in pure VO₂ was found to be suppressed by cerium inclusion.

Keywords: vanadium dioxide, luminous transmittance, phase transition temperature