Superlattice Material for the Multi-Junction Thermophotovoltaics Lattice Matched to InP

Power conversion in a thermophotovoltaic (TPV) or any other photovoltaic device can be increased by implementing monolithically series connected multibandgap structure in the device. The main concern for the multi-band gap device is the availability of different band gaps for the optimal operation of the device. Based on the recent work, GaAsN/InAsN superlattice lattice matched to InP has shown the potential of achieving band gaps in the range of 0.7-0.35eV, which is technologically important range for the TPV structure due to the availability of the photon energies in this range from the heat source. Integration of such a strain balanced superlattice structures in the conventional 0.74eV InGaAs p-i-n junction diode to produce multi-bandgap monolithically series connected devices is discussed. It is shown that these devices could surpass the performance of the bulk-like lattice mismatched InGaAs TPV converters, enabling the multi-junction tandem cell on InP