Near-field radiative heat transfer between doped silicon nanowire arrays

In this letter, we investigate the near-field radiative heat transfer between two doped silicon nanowire arrays separated by a vacuum gap. Using effective medium theory and fluctuational electrodynamics, the radiative heat transfer is calculated for the silicon nanowire arrays with different filling fractions at different vacuum gaps. The energy transfer increases as the nanowire array becomes less dense due to enhancement in channels available for heat transfer. To further understand the impact of filling fraction to the total heat transfer, the dispersion relation of coupled surface plasmon polaritons is calculated inside the vacuum gap by considering temperature-dependent dielectric functions for the doped silicon nanowires. When the filling fraction is 0.5, the radiative heat transfer at a vacuum gap of 20 nm between the nanowire arrays is almost three times of that between two doped silicon plates. Results from this study will facilitate the application of doped silicon nanowires for energy harvesting and thermal management.