MOVPE grown Ga 1−x In x As solar cells for GaInP/GaInAs tandem applications

Lattice-mismatched Ga1−xInxAs solar cells with an absorption edge between 900 and 1150 nm have been grown on GaAs substrates. Different graded Ga1−xInxAs buffer layers and solar cell structures were evaluated to achieve a good electrical performance of the device. External quantum efficiencies comparable to our best GaAs solar cells were measured. The best 1 cm2 cell with a bandgap energy of 1.18 eV has an efficiency of 22.6% at AM1.5g and a short circuit current density of 36.4 mA/cm2. To our knowledge, this is the highest reported efficiency for a Ga0.83In0.17As solar cell.