Development of the monolighically interconnected InGaP/GaAs dual junction solar cell with bypass diode for ultrahigh concentrator application

The monolithic integrated series-connected InGaP/GaAs dual junction (2J) cells with bypass diodes were demonstrated in order to achieve the ultra high concentrator application. The current-voltage (I-V) characteristics for 10 series-connected 2J cell under the dark condition showed each sub-cell was successfully interconnected each other. Epitaxially grown 2J solar cell on the semi-insulating (SI) GaAs substrate was used for electrical isolation. However, the significant deterioration of the fill factor (FF) in light I-V was apparent due to the current leakage caused by intrinsic carrier excitation in SI-GaAs. Finally, improved cell performance was achieved by applying shading layer for preventing illumination to the SI-GaAs layer.