Multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate

Quantum dot solar cells (QDSCs) comprised of 10 stacked pairs of strain-compensated InGaAs/GaNAs QD structure have been fabricated by atomic hydrogen assisted molecular beam epitaxy (H-MBE). A 3 dimensionally well ordered InGaAs QD array structure with a total density of ~10¹² cm^-2 has been achieved on GaAs (311)B substrate. The external quantum efficiencies of InGaAs/GaNAs QDSCs increase in the longer wavelength range due to additive contribution from QD layers inserted in the intrinsic region. We have achieved a higher short-circuit current density of 18.7 mA/cm² compared to an InAs/GaNAs QDSC fabricated on GaAs (001).