Development of Epoxy Bonding Techniques for III-V on Silicon Tandem Solar Cells

Tandem solar cells, integrating III-V and silicon materials, represent a promising approach for enhancing the efficiency of silicon solar cells. Several challenges, such as optimizing the thickness of the active region, removing the substrate and processing the GaAs top solar cell, ensuring long-term stability (mechanical and electrical), and reducing costs, must be overcome to achieve this goal, including bonding both materials. Bonding III-V and Si with epoxy is a less complex to heteroepitaxy. In this work we study the epoxy application technique and characterize the optical properties of the a Si SC with epoxy, glass and GaAs materials, to assess their impact on multi-junction solar cell performance. The epoxy (EPOTEK353 ND) and glass slides, were selected for their high transmittance (above 95%) and cost-effectiveness. This process resulted in a reduction of short circuit current density below 4.7%.