Vanadium dioxide radiative thermal transistor achieves hundredfold amplification of far-field heat current
Résumé
We experimentally demonstrate the operation of a radiative thermal transistor capable of switching, modulating, and amplifying far-field heat currents. This three-terminal device exploits the metal-insulator transition of VO2 thin films deposited on both surfaces of a substrate using pulsed laser deposition (PLD). This phase transition induces a sharp variation of the infrared emissivity of the VO2/substrate/VO2 system acting as the transistor base placed in between two heat-flux sensors playing the roles of the emitter and collector. Unlike previous studies, we consider substrates of r-cut and c-cut sapphire, and Si/SiO2 to correlate different microstructural properties of VO2 to its emissivity variations and optimize the thermal performance of the developed thermal transistor. By measuring the heat fluxes emitter-base and base-collector, we find that the thermal transistor implemented with a VO2/SiO2/Si base exhibits the highest thermal switching efficiency (3.6) and the largest modulation amplitude (60 W/m²), while the VO2 on r-sapphire base yields the highest amplification factor of 126. These record figures of merit underscore the critical role of the VO2 substrate selection and demonstrate the potential of radiative thermal transistors for advanced thermal management applications.
Radiative heat transfer plays a crucial role in energy management, photovoltaic conversion, temperature control, and, more recently, thermal information processing. Over the past decade, advances in heat management have encouraged the emergence of thermotronic science. Inspired by classical electronics, this field treats heat transfer similarly to electrical current, with thermal flow driven by a temperature gradient instead of an electrical potential difference. The goal is to exploit heat flow, often seen as wasted energy, for computational applications. In this emerging framework, thermal computing refers to the concept of performing logic operations and information processing using temperature gradients and heat currents, rather than electric charge or voltage. This approach could enable the development of thermal logic gates, memory elements, and signal amplifiers that operate in environments where electronic circuits are impractical or inefficient. In this context, thermal information processing has been explored through the design of devices such as thermal diodes [1-4], transistors [5-11], memristors [12-14] and logic gates [15] using smart materials with tunable properties. Among these materials, phase change
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