Impact of buffer architecture on the performance of heterogeneously integrated III-V-on-Si solar cells

We have demonstrated the impact of buffer architectures on the performance of 1J GaAs solar cells heterogeneously integrated on Si. An all-epitaxial molecular beam epitaxy-grown thin (<;1 μm) hybrid GaAs/Ge “virtual” buffer approach provided 1J GaAs cell efficiency of ~10% on Si, as compared with cell structures with thick 3 μm GaAs buffers. Solar cell results were further corroborated with materials analysis to provide a clear path for the reduction of performance-limiting dislocations. The thin “Ge-on-Si” virtual buffer approach to III-V-on-Si cell structures in the current work indicates a promising future for monolithically integrated, low-cost and high-efficiency III-V-on-Si photovoltaics.