Executive Summary : | Reversible metal-to-insulator transition (MIT) behaviors have received much research interest owing to the drastic change in their electrical resistivity and optical dielectric properties, thereby having exciting applications in various devices including sensors, switches, thermal actuators, electrochromics, and Mott transistors. One such material among these strongly correlated oxides is VO₂, which undergoes a first-order phase transition from monoclinic (semiconductor) to tetragonal rutile (metal) phase at a relatively low phase transition temperature (Tc) of ~341K. Further, the modulation of Tc can help broaden its application and help understand the phase-transition mechanism. This can be achieved by doping, external electric field, light irradiation, and strain engineering. In addition, fabricating VO₂-based nanocomposite also tunes the Tc due to the energy band structure reconstruction at the VO₂ interface. In this research proposal, VO₂-based nanocomposite having different metallic phase (eg: Au, Ni, Pt) will be fabricated enabling coupled functionalities and metamaterial properties. Tunability in the physical properties will be achieved through (i) changing the nanocomposite morphology by varying the growth kinetics including the growth temperature and oxygen partial pressure, (ii) introducing different secondary metallic phases to tune the Tc by changing the band structure and , and (iii) strain engineering by exploring different substrates (such as sapphire, strontium titanate, silicon), choice of base crystal surface and the thickness of the film. Structural characterization will be performed using XRD, HR-(S)TEM to determine the growth quality followed by the property characterization using Physical Property Measurement System (PPMS) and spectroscopic ellipsometry to measure the Tc and dielectric function. |