We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states and that a >10× higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets. In all cases, we find that carrier mobility is a crucial parameter for the performance of a radiative thermal switch. Furthermore, we derive shape-agnostic analytical approximations for the resonant heat transfer that provide general scaling laws and allow for direct comparison between different resonator geometries dominated by a single mode. The presented scheme is relevant for active thermal management and energy harvesting as well as probing excited-state dynamics at the nanoscale.
Bibliographical noteFunding Information:
O.I., N.H.T., M.C.S, A.J.M., and H.A.A. were supported as part of the DOE “Light-Material Interactions in Energy Conversion” Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DE-SC0001293. O.I., M.C.S., and H.A.A. acknowledge support from the Northrop Grumman Corporation through NG Next. M.C.S. acknowledges fellowship support from the Resnick Sustainability Institute. O.D.M. was supported by the Air Force Office of Scientific Research under award no. FA9550-17-1-0093. T.C. was supported by the Danish Council for Independent Research (grant DFFC6108-00667). M.S. was supported as part of the Army Research Office through the Institute for Soldier Nanotechnologies under contract no. W911NF-13-D-0001 (photon management for developing nuclear-TPV and fuel-TPV mm-scale-systems). M.S. was also supported as part of the S3TEC, an Energy Frontier Research Center funded by the US Department of Energy under grant no. DE-SC0001299 (for fundamental photon transport related to solar TPVs and solar-TEs).
- near-field radiative heat transfer
- surface plasmon
- thermal radiation