Abstract

Direct conversion of heat to electricity using Thermophotovoltaic (TPV) systems is attracting renewed attention due to recent advances on low bandgap (0.5-0.7 eV) III-V semiconductor materials and devices. TPV systems utilize the same principle of operation as solar cells. In particular, a heat source radiatively emits photons which are incident on a semiconductor TPV device. Photons with energy greater than the semiconductor bandgap, E_g (typically ranging from 0.50 eV to 0.73 eV for TPV devices), excite electrons from the valence band to the conduction band. The resultant electron-hole pairs are then collected by metal contacts and can power electrical loads. Photons with energy less than the semiconductor bandgap are parasitically absorbed as heat. In order to increase the efficiency of a TPV system, some form of spectral control is used to reflect photons with energy less than the semiconductor bandgap back to the radiator.

© 1998 Optical Society of America