Effect of 1 MeV electron irradiation on TiO2/Al2O3/MgF2 anti-reflective coating for GaInP/InGaAs/Ge triple junction solar cells

In this study, a high performance TiO 2 / Al 2 O 3 / MgF 2 multilayer anti-reflective (AR) coating, with an average reflectivity of 6.36% in spectral range of 300–1800 nm, applied on GaInP/GaAs/Ge triple-junction solar cell was designed by Essential Macleod Program (EMP) software. Based on the simulation results, TiO 2 , Al 2 O 3 , MgF 2 single layer and TiO 2 / Al 2 O 3 / MgF 2 multilayer AR coating samples were grown by Electron Beam Evaporation (EBE) system for 1 MeV electron beam irradiation experiment. The overall reflectivity of TiO 2 / Al 2 O 3 / MgF 2 multilayer AR coating is decreased with the increase of electron irradiation fluence due to the change of reflectivity of each AR layer caused by the refractive index changes. This result indicates that the TiO 2 / Al 2 O 3 / MgF 2 multilayer AR coating can improve the triple junction solar cell radiation resistance by achieving favorable permeability in the broadband solar spectrum, especially in 750–900 nm region where the main degradation spectral window for triple junction solar cell.