Design of CuO anti-reflection structure for thin-film thermoelectric generator

Abstract

Copper oxide anti-reflection structures were designed by rigorous coupled wave analysis for thin-film thermoelectric solar generator. We proposed thin-film thermoelectric generator with the anti-reflection structure on the hot side of pn junction. When infrared solar light from 800 to 1200 nm wavelength is irradiated to the thermoelectric generator, the anti-reflection structure on the hot side generates the temperature gradient between the hot side and cold side of pn junction. When the cross-sectional geometry of the anti-reflection structures was hemisphere which was geometrically approximated pyramid one, the reflectance from 800 to 1200 nm wavelength was reduced than flat and binary ones. The reflectance of solar light was obtained by considering the solar light spectra and its polarization. By assuming that the average of TM and TE polarized light was the reflectance of solar light, the reflectance was reduced to be 9.6% when the period of the anti-reflection structure was 700 nm. Taking into account of the reflectance of Cu on cold side 99%, this large reflectance difference is expected to generate a large temperature gradient between hot side and cold side.