Structural, electrical, and electromagnetic properties of nanostructured vanadium dioxide thin films

High-quality, phase-change vanadium dioxide (VO2), and tungsten (W)-doped VO2 thin films were synthesized using a pulsed laser deposition system and comprehensively studied using structural, electrical, microwave, and optical measurements. The nanostructures and compositions were characterized using X-ray diffraction, Rutherford backscattering, scanning electron microscopy, X-ray photoelectron spectroscopy, and high-angle annular dark-field images recorded in a scanning transmittance electron microscope. The electrical resistivity ratio was in the order of 104 and the microwave transmission ratio was greater than 25 dB between the insulating and metallic states. Additionally, the measured complex refractive indices obtained from ellipsometry were comparable to the values reported in the literature. Moreover, the films preheated to 50°C exhibited switching times in the order of milliseconds between the insulating and metallic states.