Broad Range Tuning of Phase Transition Property in VO₂ Through Metal‐Ceramic Nanocomposite Design

Abstract

Abstract Vanadium dioxide (VO 2 ) is a well‐studied Mott‐insulator because of the very abrupt physical property switching during its semiconductor‐to‐metal transition (SMT) around 341 K (68 °C). In this work, through novel oxide‐metal nanocomposite designs (i.e., Au:VO 2 and Pt:VO 2 ), a very broad range of SMT temperature tuning from ≈ 323.5 to ≈ 366.7 K has been achieved by varying the metallic secondary phase in the nanocomposites (i.e., Au:VO 2 and Pt:VO 2 thin films, respectively). More surprisingly, the SMT T c can be further lowered to ≈ 301.8 K (near room temperature) by reducing the Au particle size from 11.7 to 1.7 nm. All the VO 2 nanocomposite thin films maintain superior phase transition performance, i.e., large transition amplitude, very sharp transition, and narrow width of thermal hysteresis. Correspondingly, a twofold variation of the complex dielectric function has been demonstrated in these metal‐VO 2 nanocomposites. The wide range physical property tuning is attributed to the band structure reconstruction at the metal‐VO 2 phase boundaries. This demonstration paved a novel approach for tuning the phase transition property of Mott‐insulating materials to near room temperature transition, which is important for sensors, electrical switches, smart windows, and actuators.