PbSnSe/PbSrSe quantum well materials for thermophotovoltaic devices

Abstract

Multiple quantum well (MQW) materials composed of Pb0.81Sn0.19Se wells and Pb0.80Sr0.20Se 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.

Materials and device designs for thermophotovoltaic power conversion

“…The photogenerated charge collection model described here shows that short circuit current densities with a 1400°C radiator are expected to be in the range of 2.3 to 5.3 A/cm 2 depending on material quality and optical coatings. As shown previously, 17 open circuit voltage for small bandgap materials can be a large fraction of E g / q when short circuit densities are large. For example, a 450 meV bandgap material will have an open circuit voltage of 182.3 mV at a short circuit current density of 0.5 A/cm 2 , while at a short circuit current density of 5 A/cm 2 open circuit voltage increases more than 30% to 241.8 mV.…”

“…For example, a 450 meV bandgap material will have an open circuit voltage of 182.3 mV at a short circuit current density of 0.5 A/cm 2 , while at a short circuit current density of 5 A/cm 2 open circuit voltage increases more than 30% to 241.8 mV. As described in Khodr et al, 17 this effect can make it worthwhile to incorporate small bandgap materials into TPV device designs when large short circuit densities are possible.…”

“…MQW materials will thus have a band structure composed of a lower energy normal valley subband and three degenerate oblique valley subbands at a higher energy as indicated in Figure 2. With this subband structure, the effective density of states will be smaller than that for a bulk material with a similar bandgap energy, an effect that reduces reverse bias saturation current and increases open circuit voltage 17 . Figure 3 shows interband transition energies in Pb 0.8 Sr 0.2 Se/Pb 0.81 Sn 0.19 Se/Pb 0.8 Sr 0.2 Se MQW materials plotted as a function of Pb 0.81 Sn 0.19 Se well width.…”

Analytical Model of InP QWs for Efficiency Improvement in GaInP/Si Dual Junction Solar Cell

“…[ 42 ] PbSnSe/PbSrSe QW materials were grown on PbSe and Si substrate using MBE process with high epilayer quality. [ 45 ] The MBE has made easily possible to grow the QW layers, which are 7 nm or less than 7 nm thickness. This doesn't require extra cost for different production unit, but still this growth process of extra layers requires some extra cost.…”

“…The numerical modeling of the SC is performed using Silvaco ATLAS TCAD Tool and American Society for testing and Materials (ASTM)-certified AM1.5G spectrum is used to illuminate SC. [45] 2. Quantum Well Incorporation In GaInp/Si Dual Junction Solar Cell…”