Radiation Hardening of Dual Junction Solar Cells

We report on integration of wavelength selective photonic structures (WSPS) such as distributed bragg reflectors (DBR) and multi quantum well structures to InGaP-GaAs dual junction (DJ) and GaAs single junction (SJ) solar cells. Epitaxial lift Off (ELO) process compatible InAlP-InGaP DBR structures and strain balanced GaAsP-InGaAs MQW developed. Subcell voltages for DJ cells were extracted from EL measurements. EQE data for GaAs sub cells was modeled and compared with experimental data. 1MeV Electron radiation studies performed to evaluate the radiation hardness of these ELO DJ cells with integrated DBR exhibited 12% improvement in remaining factor P/P
₀
values (EoL performance for 1E15 electron irradiation) when compared with baseline DJ cell with no DBR.