Impacts of optical properties of anti-reflection coatings on characteristics of InGaP/GaAs/Si hybrid triple-junction cells

InGaP/GaAs/Si hybrid triple-junction cells with 95-nm SiN/65-nm SiO2 bilayer and 75-nm SiN monolayer films as anti-reflection (AR) coatings were investigated. A more marked imbalance in photo currents of subcells was observed in cells with SiN monolayer films. The difference in imbalance was attributed to the optical properties of coatings. The short-circuit currents of the two triple-junction cells were close to each other and were larger than photo currents in the Si bottom cells while the open-circuit voltages were slightly different. These findings suggested that subcells might be electrically coupled to each other in multijunction operations.