Debu Desalegn T, Doha M Hasan, Churchill Hugh O H, Herzog Joseph B
Department of Physics, University of Arkansas Fayetteville Arkansas 72701 USA
Institute of Nanoscale Science and Engineering, University of Arkansas Fayetteville Arkansas 72701 USA.
RSC Adv. 2019 Sep 17;9(50):29173-29181. doi: 10.1039/c9ra04695j. eCollection 2019 Sep 13.
Plasmon coupling and hybridization in 2D materials plays a significant role for controlling light-matter interaction at the nanoscale. We present a near-field radiation heat transfer (NFRHT) between vertically separated graphene and black phosphorene sheets at different temperatures in nanoscale separations. Radiation exchange from the theory of fluctuation electrodynamics is modulated by the carrier density of graphene and phosphorene. Direct comparison of NFRHT black phosphorene-graphene to symmetric graphene-graphene radiation exchange can be as much as 4 times higher for the selected doping range in both armchair (AC) and zigzag (ZZ) orientations of BP. The strong NFRHT enhancement of the specific optical properties of the heterogenous 2D material is due to the strong coupling of propagating surface plasmon polaritons as demonstrated by the distribution of the heat transfer coefficient. We also demonstrate that the magnitude of the near-field radiation enhancement is found to acutely depend on the vacuum gap of the graphene and BP pair. Interestingly, for separation distances below 200 nm, the total near-field heat transfer between black phosphorene and graphene exceeds that between graphene and graphene by 5 times. The radiation enhancement can be further tuned based on the orientation, AC, and ZZ of black phosphorene. These results prominently enable dynamic control of the total NFRHT relying on tunable anisotropic characteristics of BP irrespective of graphene's optical conductivity. Furthermore, the heterogeneous pairs of 2D materials potentially provide alternative platforms to achieve beyond super-Planckian radiation.
二维材料中的等离激元耦合和杂化在控制纳米尺度的光与物质相互作用方面发挥着重要作用。我们展示了在纳米尺度间距下，垂直分离的石墨烯和黑磷烯片在不同温度之间的近场辐射热传递（NFRHT）。波动电动力学理论中的辐射交换受到石墨烯和磷烯载流子密度的调制。对于扶手椅（AC）和锯齿（ZZ）取向的黑磷（BP），在选定的掺杂范围内，NFRHT黑磷烯 - 石墨烯与对称的石墨烯 - 石墨烯辐射交换的直接比较可高出多达4倍。如传热系数分布所示，异质二维材料特定光学性质的强烈NFRHT增强是由于传播表面等离激元极化子的强耦合。我们还证明，近场辐射增强的幅度被发现强烈依赖于石墨烯和BP对的真空间隙。有趣的是，对于低于200 nm的分离距离，黑磷烯与石墨烯之间的总近场热传递超过石墨烯与石墨烯之间的热传递5倍。辐射增强可以基于黑磷烯的取向、AC和ZZ进一步调节。这些结果显著地实现了基于BP可调各向异性特性对总NFRHT的动态控制，而与石墨烯的光导率无关。此外，二维材料的异质对有可能提供替代平台以实现超越普朗克辐射。
