Characterization and Simulation of AlGaAsSb/GaSb Tandem Solar Cell

Antimonide-based alloys have gained interest in the field of multijunction solar cells thanks to their ability to grow a broad range of bandgaps (0.27–1.64 eV) lattice-matched on GaSb. Recent studies have demonstrated the potential of the AlGaAsSb alloy as active material in solar cells. However, only a few solar cells have been effectively produced and characterized. In this article, we report on the fabrication and characterization of a tandem AlGaAsSb/GaSb solar cell, as well as a single AlGaAsSb solar cell. As the AlGaAsSb junction in the tandem solar cell suffers from a low shunt resistance, this article also introduces an alternative and simple method for the quantum efficiency measurement of tandem solar cells with low shunt resistances. Short diffusion lengths of minority carriers in the AlGaAsSb alloy are found to limit the conversion efficiency of the solar cell.