InGaAs quantum well-dots based GaAs subcell with enhanced photocurrent for multijunction GaInP/GaAs/Ge solar cells

MOCVD-grown GaAs single-junction solar cells (SC) with quantum well-dots (QWD) were fabricated and tested. The QWD were formed by the deposition of In_0.4Ga_0.6As layers separated with GaAs spacers. A remarkable improvement of photocurrent was achieved and the reduction of open-circuit voltage was partly suppressed by decreasing the spacers' growth rate as well as increasing their thickness up to 40 nm. Based on the experimentally obtained characteristics of these single-junction SCs we estimated that using QWD media in the middle (GaAs-based) subcell can provide 1 abs. %, increasing the efficiency of the triple-junction GaInP/GaAs/Ge SCs. (paper)