Near-field radiative thermal rectification assisted by black phosphorus sheets

Abstract

We suggest a thermal rectification structure where a semi-infinite InSb plate and a semi-infinite 3C–SiC plate coated by black phosphorus (BP) sheets are separated by a nanoscale vacuum gap. To obtain high and tunable thermal rectification efficiency, we employ the temperature-dependent dielectric properties of both InSb and 3C–SiC, and introduce BP sheets with in-plane anisotropy into the structure. Based on fluctuational electrodynamics, the near-field radiative heat transfer and the rectification efficiency are calculated. It is found that the rectification efficiency varies very sensitively with the emitter's temperature, the chemical potential and the number of BP layers, thus opening up possibilities to control the rectification efficiency through these parameters. Higher rectification efficiencies are obtained under some certain conditions, and the origins of the thermal rectification effect are elucidated in some detail. The obtained results might be helpful in designing a BP-based high-efficiency thermal diode.