InGaP/GaAs and InGaAs mechanically-stacked triple-junction solar cells

Abstract

Triple-junction cells with AM1.5 efficiencies of over 33% have been demonstrated. A planar type InGaP/GaAs monolithic dual-junction cell was fabricated on a semi-insulating GaAs substrate, which has high infra-red transparency. Then a dual-junction cell, with an efficiency of 27-28%, was mechanically stacked on an InGaAs cell fabricated on an InP substrate. The bottom InGaAs cell showed a efficiency of 6.2% under the InGaP/GaAs cell, and a total efficiency of 33-34% was achieved for the four-terminal triple-junction cell.