Patent ID: 8536446

Claim:
A multijunction solar cell comprising: a first solar subcell composed of InGa(Al)P and having a first band gap; a second solar subcell disposed over said first solar subcell and having a second band gap smaller than said first band gap, the second solar subcell being composed of In 0.015 GaAs; a grading interlayer composed of InGaAlAs disposed over said second solar subcell and having a third band gap that is constant throughout its thickness and greater than said second band gap; and a third solar subcell disposed over said interlayer that is lattice mismatched with respect to second solar subcell and having a fourth band gap smaller than said third band gap, the third solar subcell being composed of In 0.30 GaAs, wherein the grading interlayer achieves a transition in lattice constant from the second solar subcell to the third solar subcell.