Surface Roughness, Residual Stress, and Optical and Structural Properties of Evaporated VO2 Thin Films Prepared with Different Tungsten Doping Amounts

This study investigates the effects of different tungsten (W) doping contents on the optical transmittance, surface roughness, residual stress, and microstructure of evaporated vanadium dioxide (VO2) thin films. W-doped VO2 thin films with varying tungsten concentrations were fabricated using electron beam evaporation combined with ion-assisted deposition techniques, and deposited on silicon wafers and glass substrates. The optical transmittances of undoped and W-doped VO2 thin films were measured by UV/VIS/NIR spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The root mean square surface roughness was measured using a Linnik microscopic interferometer. The residual stress in various W-doped VO2 films was evaluated using a modified Twyman–Green interferometer. The surface morphological and structural characterization of the W-doped VO2 thin films were performed by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Raman spectroscopy was used to analyze the structure and vibrational modes of different W-doped VO2 thin films. These results show that the addition of tungsten significantly alters the structural, optical, and mechanical properties of VO2 thin films.