Four-junction heterovalent solar cells based on II-VI/III-V/Ge coherent and metamorphic heterostructures

We present original design and performance simulations of four‐junction heterovalent concentrator solar cells with monolithically integrated junctions based on Ge, III–V, and II–VI semiconductors. The developed design relies on the formation of a metamorphic buffer layer matching lattice constants of a Ge junction and three more junctions based on InGaAs, AlInGaAs, and a ZnSe/CdSe short‐period superlattice. Utilizing of an n+‐type chlorine‐doped layer of ZnCdMgSe as a highly transparent conductive window is proposed. Experimental results are reported, demonstrating the potential of molecular beam epitaxy to fabricate such solar cell heterostructures atop of a Ge p–n junction formed in a Ge substrate.