A Thermal Diode Based on Nanoscale Thermal Radiation.

Fiorino, Anthony; Thompson, Dakotah; Zhu, Linxiao; Mittapally, Rohith; Biehs, Svend-Age; Bezencenet, Odile; El-Bondry, Nadia; Bansropun, Shailendra et al. · ACS Nano · 2018

basic_science · Level V

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Abstract

In this work we demonstrate thermal rectification at the nanoscale between doped Si and VO<sub>2</sub> surfaces. Specifically, we show that the metal-insulator transition of VO<sub>2</sub> makes it possible to achieve large differences in the heat flow between Si and VO<sub>2</sub> when the direction of the temperature gradient is reversed. We further show that this rectification increases at nanoscale separations, with a maximum rectification coefficient exceeding 50% at ∼140 nm gaps and a temperature difference of 70 K. Our modeling indicates that this high rectification coefficient arises due to broadband enhancement of heat transfer between metallic VO<sub>2</sub> and doped Si surfaces, as compared to narrower-band exchange that occurs when VO<sub>2</sub> is in its insulating state. This work demonstrates the feasibility of accomplishing near-field-based rectification of heat, which is a key component for creating nanoscale radiation-based information processing devices and thermal management approaches.