Photonic crystal resonant cavity for thermophotovoltaic applications

The ability to efficiently transform heat into a usable energy using thermophotovoltaics (TPV) has been a topic of research for many years. Due to recent micro fabrication advances, TPV and photonic crystals (PhC) has been the subject of renewed interest. In particular, PhC have been shown to increase the efficiency of photon to current conversions for infrared photodetectors. Here, Photonic crystals and a back reflecting plane have been employed to increase the efficiency of TPV cells by creating a resonant cavity. The result is an increased interaction time between photons and excitons leading to an increase in electron/hole pair generation. A simulated 2D photonic crystal consisting of Si₃N₄ rods in an ohmic contact material has demonstrated a possible 81% increase in absorption for a GaSb TPV cell.