Fabrication of High-Efficiency III–V on Silicon Multijunction Solar Cells by Direct Metal Interconnect

This paper presents a novel direct-metal-interconnect hybrid integration method for the fabrication of low cost and high-efficiency multijunction solar cells without being constrained by lattice matching requirements. It also incorporates the areal current matching technique that is essential in mitigating the adverse effects of current limiting by the Si subcell to achieve maximum possible efficiency. A GaInP/InGaAs/Si triple-junction solar cell has been demonstrated, with a 2-terminal estimated efficiency of 25.5% tested under a filtered Xe arc lamp with the light intensity set to 100 mW/cm2. The cell shows promising thermal reliability, as well as potential for operation under concentrated illumination.