The effect of UV-activated hydrogenation on the performance of GaInNAs solar cells is presented. A proof-of-principle investigation was performed on non-optimum GaInNAs cells, which allowed a clearer investigation of the role of passivation on the intrinsic nitrogen-related defects in these materials. Upon optimized hydrogenation of GaInNAs, a significant reduction in the presence of defect and impurity based luminescence is observed as compared to that of unpassivated reference material. This improvement in the optical properties is directly transferred to an improved performance in solar cell operation, with a more than two-fold improvement in the external quantum efficiency and short circuit current density upon hydrogenation. Temperature dependent photovoltaic measurements indicate a strong contribution of carrier localization and detrapping processes, with non-radiative processes dominating in the reference materials, and evidence for additional strong radiative losses in the hydrogenated solar cells.

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-An InAs/GaAs0. 86Sb0.14 QDSC and a GaAsSb control cell were investigated using temperature dependent J-V, external quantum efficiency (EQE), photoluminescence (PL) and electroluminescence (EL) measurements. Thermally activated defect states associated with the GaAsSb matrix materials are found to account for the reduction of the performance of the solar cell. The rapid quenching of the PL and EL intensity, along with the shift (above 150 K) of the dominant recombination process during spontaneous emission (EL) further indicate the prevalence of non-radiative processes at elevated temperatures in these systems. These findings are supported by a reduction in the open circuit voltage at elevated temperatures in these devices.

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