Semiconductor-based selective emitter with a sharp cutoff for thermophotovoltaic energy conversion

A semiconductor emitter can possibly achieve a sharp cutoff wavelength due to its intrinsic bandgap absorption and almost zero sub-bandgap emission without doping. A germanium-wafer-based selective emitter with front-side antireflection and backside metal coating is studied here for thermophotovoltaic (TPV) energy conversion. Optical simulation predicts the spectral emittance above 0.9 in the wavelengths from 1 to 1.85 mu m and below 0.2 in the sub-bandgap range with a sharp cutoff around the bandgap, indicating superior spectral selectivity behavior. This is confirmed by excellent agreement with indirectly measured spectral emittance of the fabricated Ge-based selective emitter sample. Furthermore, the TPV efficiency by pairing the Ge-based selective emitter with a GaSb cell is theoretically analyzed at different temperatures. This Letter facilitates the development of the semiconductor-based selective emitters for enhancing TPV performance. (C) 2021 Optical Society of America

Automated summary

This study focuses on a germanium-wafer-based selective emitter for thermophotovoltaic energy conversion, showing superior spectral selectivity behavior and high efficiency. Optical simulation and experimental results confirm the sharp cutoff wavelength and spectral emittance of the emitter, supporting the development of semiconductor-based selective emitters for enhancing TPV performance.