Numerical study on tungsten selective radiators with various micro/nano structures

To develop microstructured selective radiators for TPV generation, numerical simulations based on the finite-difference time-domain method were carried out to evaluate spectral properties of various types of surface micro/nano structures: two-dimensional surface-relief gratings with various surface structures such as rectangular holes, cylindrical holes, and micro-pyramids. It was shown that cylindrical holes as well as rectangular holes also realize the cutoff effect with different cutoff wavelengths. On the other hand, W gratings with micro-pyramid array showed high emissivity near unity in the near infrared region due to the anti-reflection effect based on sub-wavelength gratings.