MOVPE grown Ga{sub 1{minus}x}In{sub x}As solar cells for GaInP/GaInAs tandem applications

Lattice-mismatched Ga{sub 1{minus}x}In{sub x}As solar cells with an absorption edge between 900 and 1,150 nm have been grown on GaAs substrates. Different graded Ga{sub 1{minus}x}In{sub x}As buffer layers and solar cell structures were evaluated to achieve a good electrical performance of the device. External quantum efficiencies comparable to the best GaAs solar cells were measured. The best 1 cm{sup 2} cell with a bandgap energy of 1.18 eV has an efficient of 22.6% at AM1.5g and a short circuit current density of 36.4 mA/cm{sup 2}. To the authors knowledge, this is the highest reported efficiency for a Ga{sub 0.83}In{sub 0.17}As solar cell.