Title: High-efficiency InAs/GaAs quantum dot solar cells by metalorganic chemical vapor deposition
Abstract: We fabricate a high-efficiency InAs/GaAs quantum dot (QD) solar cell. It contains five layers of high-density self-assembled InAs QDs grown by metalorganic chemical vapor deposition suppressing open-circuit-voltage (VOC) degradation. We develop a dual-layer anti-reflection coating of optimum thicknesses. The resulting cell exhibits efficiencies of 18.7% under AM1.5 G for 1 sun and 19.4% for 2 suns. Concentrator measurements demonstrate the advantage of QD use under concentrated illumination, owing to the significant increase in VOC. We also find a VOC offset of 0.3 V from the QD ground-state transition energies for QD cells, in contrast to 0.4 V for state-of-the-art bulk semiconductor cells.