VO2 being a transition metal oxide is the most fascinating material of research as it shows a semiconductor to metal transition (SMT) near to room temperature (TSMT ~ 68 οC). It undergoes a structural change from M1, monoclinic phase (Space group: P21/c) to R, tetragonal phase (Space group: P42/mnm).1 Due to this phase transition, it is used for various applications like smart windows, metamaterial, bolometers, etc.2 Herein, we report the synthesis of device quality VO2 thin films. Various methods like home-built Ultrasonic Nebulised Spray Pyrolysis of Aqueous Combustion Mixture (UNSPACM)3, Chemical Vapor Deposition (CVD)4, Pulsed Laser Deposition (PLD) and DC Reactive sputtering have been employed for the synthesis of phase pure VO2 thin films. The structural characterization has been carried out by XRD and Raman measurements which confirms the M1 phase of VO2 at room temperature followed by high-temperature measurements to study the phase change. Temperature-dependent resistance measurements confirm the SMT transition at TSMT ~68 οC with a three-four order of magnitude change in resistance. Temperature-dependent IR measurements show ~80% change in reflectance across the phase transition where the thin film acts as an IR reflector (T>TSMT). Effect of dopant (W, Mo, Sc, Ce etc.) has been studied where the TSMT was reduced to 25 οC with 2 at % W doping. Our preliminary attempts to make metamaterials will also be presented.
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