Abstract
In this paper, VO2 thin films with good optical properties are fabricated on practical float glass by magnetron sputtering and a professional annealing method. The near-infrared switching efficiency (NIRSE) of the prepared film reaches 39% (@2000 nm), and its near-infrared energy modulation ability (ΔTir) reaches 10.9% (780-2500 nm). Further, the highest integral visible transmittance Tlum is 63%. The proposed method exhibits good reproducibility and does not cause any heat damage to the magnetron sputtering machine. The crystalline structure of the VO2 film is characterized by X-ray diffraction (XRD). The lattice planes (011) and (-211) grow preferentially (JCPDS 65-2358), and a large number of NaV2O5 crystals are detected simultaneously. The microstructures are characterized by scanning electron microscopy (SEM), and a large number of long sheet crystals are identified. The phase transition temperature is significantly reduced by an appropriate W doping concentration (Tc = 29 °C), whereas excessive W doping causes distortion of the thermal hysteresis loop and a reduction in the NIRSE. Oxygen vacancies are created by low pressure annealing, due to which the phase transition temperature of VO2 film decreases by 8 °C. The addition of an intermediate SiO2 layer can prevent the diffusion of Na+ ions and affect the preparation process of the VO2 thin film.