Investigation of Radiative Coupling from InGaAsP Quantum Wells for Improving End-of-Life (EOL) Efficiency in Multijunction Solar Cells
Geoffrey K. Bradshaw1, Mitsul Kacharia2, Stephen J. Polly2, Colin J. Mann3, Hyunseong Kum4, Seth M. Hubbard2
1Air Force Research Laboratory, Albuquerque, NM, United States
/2Rochester Institute of Technology, Rochester, NY, United States
/3The Aerospace Corporation, El Segundo, CA, United States
/4Massachusetts Institute of Technology , Cambridge, MA, United States

GaInP/(In)GaAs/Ge multijunction solar cells have been state-of-practice for power generation on spacecraft for over a decade but there are still potential improvements for end-of-life (EOL) efficiency. Radiative coupling between GaInP and (In)GaAs subcells is not typically considered in the EOL design of space solar cells because radiative recombination in the GaInP is effectively quenched by radiation-induced damage. This paper shows that InGaAsP quantum well structures incorporated into a GaInP subcell may be less sensitive to radiation damage, thereby enabling radiative coupling between subcells at EOL and providing a current boost in the (In)GaAs subcell to improve EOL efficiency.