Near-field radiative heat transfer for Si based metamaterials

•We study near field radiative heat transfer for two doped Si based metamaterials: Si nanowire arrays and Si nanohole arrays.•Photon local density of states is investigated based on the fluctuational electrodynamics and effective medium theory.•The near-field thermal radiation of these two Si based metamaterials is dominated by the direct photon absorption due to the induced dipoles in Si, but not by the coupled surface polariton wave or the hyperbolic metamaterial characteristics.

Radiative heat transfer in the near field can exceed the blackbody radiation limit by orders of magnitude due to energy transfer through evanescent waves. Doped Si has attracted significant attention in studies of near field thermal radiation, since it is a Drude-type material whose plasma frequency can be tuned into the infrared range by modifying the dopant concentration. Thus, doped Si can serve as a “tunable metal” which can be used to design tunable metamaterials to control near field thermal radiation. In this paper, we study near field radiative heat transfer for two doped Si based metamaterials: Si nanowire arrays and Si nanohole arrays, using fluctuational electrodynamics and effective medium theory.