Simulation of InGaAs/InGaP multiple quantum well systems for multijunction solar cell

Multijunction solar cells hold the actual world record efficiency, converting 46% of the solar energy into electricity on ground, and are the very basis of spatial missions' power supply. Multiple quantum well systems are one of the possible solutions to overcome a major technological challenge of this type of device, namely, finding materials with appropriate bandgap and lattice parameter that can lead to current matching between the stacked pn junctions. In this work, as an alternative to face this issue, we present a theoretical study on the strain-compensated InxGa 1−x As/InyGa 1−y P multiple quantum well system to be applied as the active region in such multiple junctions. In principle, this system is expected to present more radiation hardness than the state-of-art quantum well multijunction solar cells based on InGaAs / GaAsP. Several combinations of thicknesses and compositions of wells and barriers were probed, leading to a broad range of the effective bandgap energy, from 0.7 to 1.3 eV. Some of the simulated quantum well system configurations match the optimal energies for devices containing 1 to 5 junctions for both terrestrial and spatial applications.