Emissivity Measurements of Vanadium Dioxide Thin Films through the Thermal Wave Resonant Cavity and its Applications in Radiative Thermal Diode and Transistor Simulations

•Vanadium dioxide exhibit emissivity variations within its metal-insulator transition enabling to amplify and rectify radiative heat.•VO2 thin films’ emissivity, as measured by the thermal wave resonator cavity, displays characteristics dependent on the deposition substrate.•A radiative thermal diode with a r-sapphire collector demonstrated a theoretical rectification factor of 84%.•A radiative thermal transistor with a c-sapphire base showed a theoretical amplification factor of heat flux density above 70. This study focuses on precisely measuring the emissivity of vanadium dioxide (VO2) thin films across their metal-to-insulator transitions (MIT) using the reliable thermal wave resonator cavity technique (TWRC). High quality VO2 thin films were deposited on c-sapphire, r-sapphire and Si/SiO2 substrates using pulsed laser deposition (PLD). These phase-change materials served as thermal wave generators in a standard TWRC experiment with the aim of meticulously quantifying the IR emissivity. This was achieved by analyzing the amplitude and phase of the pyroelectric signals driven by the thermal waves within the cavity. The experimental emissivity data obtained through this method have allowed us to gain valuable insights into the dynamic emissivity behavior of VO2 under the influence of different substrates, since samples displayed different MIT characteristics. For instance, the emissivity variation across the MIT was as high as Δε=0.38 and different hysteresis width sizes were also recorded for each VO2 thin film. Finally, the acquired experimental emissivity was used in modeling and simulating the functionality of the thermal diode and transistor. Exploiting the unique emissivity profiles observed in VO2 thin films, we explored the concept of a theoretical radiative thermal diode with an r-sapphire collector. Additionally, we delved into the possibilities of a radiative thermal transistor with a c-sapphire base. Our findings open up avenues for optimizing these thermal components, enabling innovative solutions for controlling heat transfer at small dimensions.