Optimization of the InGaP Top Junction of Triple Junction Solar Cell for Spatial Application

Abstract

Electrical current mismatching is a well-known limitation of triple junction solar cells that lowers the final conversion efficiency. Several solutions have been proposed to face this issue, including the insertion of a multiple quantum well structure as the intermediate junction’s active material. With a better matching in the current among the junctions, the total current increases, thus modifying the working conditions of the overall device. In this way, the InGaP top junction needs to be optimized to such new condition. In this work, numerical simulations were carried out aiming the enlargement of the electrical current density of an InGaP pn junction to achieve the proper current matching in triple junction solar cell for spatial applications. The optimized structure has been grown in a GaAs substrate and characterized as a single junction solar cell. Although the measured short circuit current density and conversion efficiency are still well below the theoretically predicted values, processing improvement should lead to adequate cell performance.