Performance and Radiation Resistance of Quantum Dot Multi-Junction Solar Cells

Lattice matched, triple-junction solar cells with strain compensated quantum dots (QDs) in the GaAs middle cell were grown by Metal-Organic Chemical Vapor Deposition (MOCVD). Devices with different numbers of QD layers are compared to baseline devices with no QDs. Quantum efficiency and light I-V measurements show an increase in short circuit current density and degradation of the open circuit voltage for QD solar cells. The QDs do not improve the overall efficiency of the devices, and the performance degrades as more QD layers are added. The QD solar cells show improved relative radiation resistance compared to baseline devices, but the improvement is insufficient to make up for the initial loss of performance.