Near-field thermal emission between corrugated surfaces separated by nano-gaps

•FDTD calculations of LDOS are given for corrugated surfaces.•FDTD calculations of heat flux are given for corrugated surfaces.•CPML is used as the optimum boundary condition for this type of work.•Rectangular, elliptical and triangular shapes were used to form corrugated surfaces.•Rectangles proved to have the highest impact on enhancement of LDOS and heat flux.

Near-field thermal radiation with its many potential applications in different fields requires a thorough understanding for the development of new devices. In this paper, we report that near-field thermal emission between two parallel SiC thin films separated by a nano-gap, supporting surface phonon polaritons, as modeled via Finite Difference Time Domain Method (FDTD), can be enhanced when structured nanoparticles of different shapes and sizes are present on the surface of the emitting films. We compare different nano-particle shapes and discuss the configurations, which have the highest impact on the enhancement of near-field thermal emission and on the near-field heat flux. Convolutional Perfectly Matched Layer (CPML) boundary condition is used as the boundary condition of choice as it was determined to give the most accurate results compared against the other methodologies when working with sub-wavelength structures.