Relationship between Transition Temperature and x in V1-xWxO2 Films Deposited by Dual-Target Magnetron Sputtering

Thin films of V1-x Wx O2 were deposited on glass and Si by dual-target sputtering and characterized by thin film X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and spectrophotometry. The relationship between x (0-0.026) and the phase transition temperature τ c (0-67° C) in the most applicable range for advanced window coatings was clarified by formation of a single-phase film and precise determination of the amount of doping. Tungsten doping linearly decreases τ c by 23° C/at.%W and also significantly reduces the thermal hysteresis loop width in optical transmittance.