GaAs for Thermophotonics: From Thin-Film Solar Cells to Highly Efficient LEDs

Thermophotonics (TPX) is a technology field that stems from thermophotovoltaics (TPV), in which the hot body of a conventional TPV system is replaced by a hot light-emitting diode (LED). Unlike a TPV system, the radiation from the emitter can be made super-thermal by electrically biasing the hot LED, enabling it to radiate more power than predicted by Planck’s law. However, the realization of such a system requires the suppression of most of the non-radiative losses in the LED and extremely efficient light coupling to the photovoltaic absorber (PV). The high quality achieved by GaAs-based devices in the recent years and the advances in the LED industry indicate that this may now be achieved. This study presents the objectives of the TPX-Power project, a project that aims to investigate the feasibility of waste thermal energy recovery using TPX devices with the currently available and emerging semiconductor technologies. The experimental challenges associated with applying the well-established fabrication of III-V thin-film solar cells into the modified devices required for the realization of the TPX devices will be explored, and preliminary results will be shown. Finally, an overview of the required steps to fully develop this technology will be discussed.