Near-field radiative heat transfer enhancement via surface phonon polaritons coupling in thin films

We investigate near-field thermal radiation between a nanometric film and a bulk SiC using fluctuational electrodynamics. Results show a narrow spectral band enhancement of the radiative flux for nanometric emitters due to coupling of surface phonon polaritons inside the film. For a 10nm thick SiC emitter, the total radiative flux is 2.2 times larger than for a bulk emitter. The total radiative flux is increased by a factor of 3.3 if a dielectric is coated with a 10nm SiC film due to a splitting of the resonant frequency into two distinct ones, which has practical interests for near-field thermophotovoltaic devices.