Gate voltage and doping effects on near-field radiation heat transfer in plasmonic heterogeneous pairs of graphene and black phosphorene

Desalegn T Debu; M Hasan Doha; Hugh O H Churchill; Joseph B Herzog

doi:10.1039/c9ra04695j

Gate voltage and doping effects on near-field radiation heat transfer in plasmonic heterogeneous pairs of graphene and black phosphorene

RSC Adv. 2019 Sep 17;9(50):29173-29181. doi: 10.1039/c9ra04695j. eCollection 2019 Sep 13.

Authors

Desalegn T Debu¹, M Hasan Doha¹, Hugh O H Churchill^{1

2}, Joseph B Herzog^{1

3}

Affiliations

¹ Department of Physics, University of Arkansas Fayetteville Arkansas 72701 USA debudt@udel.edu.
² Institute of Nanoscale Science and Engineering, University of Arkansas Fayetteville Arkansas 72701 USA.
³ R. B. Annis School of Engineering, University of Indianapolis Indianapolis IN USA 46227.

Abstract

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.