PbSnSe/PbSrSe quantum well materials for thermophotovoltaic devices

Multiple quantum well (MQW) materials composed of Pb_0.81Sn_0.19Se wells and Pb_0.80Sr_0.20Se barriers with intersubband energy gaps of 343 meV and 450 meV were modeled for thermophotovoltaic (TPV) device performance. The effect of L-valley degeneracy removal in these (111)-oriented IV-VI semiconductor quantum wells was evaluated. Degeneracy splitting reduces the effective densities of states in both the valence and conduction bands. Thermally generated intrinsic charge carrier concentrations are smaller by a factor of three as compared to bulk materials with the same bandgap energies. A current-matched dual junction TPV cell made from these MQW materials in a generator with a 1215°C radiator is predicted to have a power density of 2.34 W/cm², 49% better than the power density generated by a cell made from bulk materials with the same bandgap energies.