A study on the artifact external quantum efficiency of Ge bottom subcells in triple-junction solar cells

We have studied about the artifact EQE on Ge-subcell in triple-junction cells. The aritifact EQE relates to the anomalous behavior. The EQE relation exhibited the linear dependency agans to the artifact. We confirmed that the artifact EQE is affected with the bias voltage or the limitation of the incidence bias-light to GaAs layer. In this study, we tried to introduce these measurement conditions for investigating the artifact, before and after proton irradiation. From the results it was confirmed the individual difference on each cell. In addition, there were several patterns of the linear relation, and their behaviors were changed by the proton irradiation.