Metamorphic layers in multijunction solar cells
AssigneeSolAero Technologies Corp.
InventorsArthur Cornfeld, Mark A. Stan
Life of this patent
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Abstract
A method of forming a multijunction solar cell comprising an upper subcell, a middle subcell, and a lower subcell comprising providing first substrate for the epitaxial growth of semiconductor material; forming a first solar subcell on said substrate having a first band gap; forming a second solar subcell over said first subcell having a second band gap smaller than said first band gap; and forming a grading interlayer over said second sub cell having a third band gap larger than said second band gap forming a third solar subcell having a fourth band gap smaller than said second band gap such that said third subcell is lattice mis-matched with respect to said second subcell.
Claims21
(canceled)
A multijunction solar cell comprising:
- a first solar subcell having a first band gap;
- a second solar subcell disposed below the first solar subcell and having a second band gap smaller than the first band gap;
- an InGaAlAs grading interlayer disposed below the second solar subcell, wherein the InGaAlAs grading interlayer includes a compositionally step-graded InGaAlAs series of layers, and wherein the InGaAlAs grading interlayer has a constant third band gap throughout its thickness greater than the second band gap;
- and
- a third solar subcell disposed below the InGaAlAs interlayer that is lattice mismatched with respect to the second solar subcell and having a fourth band gap smaller than the third band gap,
- wherein the InGaAlAs grading interlayer achieves a transition in lattice constant from the second subcell to the third subcell.
A multijunction solar cell assembly comprising:
- a cover glass;
- a multijunction solar cell below the cover glass, the multijunction solar cell including:
- one or more grid lines;
- a first contact layer below the one or more grid lines;
- a window layer below the first contact layer,
- a first solar subcell disposed below the window layer and having a first band gap;
- a second solar subcell disposed below the first solar subcell and having a second band gap smaller than the first band gap;
- an InGaAlAs grading interlayer disposed below the second solar subcell, wherein the InGaAlAs grading interlayer includes a compositionally step-graded InGaAlAs series of layers, and wherein the InGaAlAs grading interlayer has a constant third band gap throughout its thickness greater than the second band gap;
- a third solar subcell disposed below the InGaAlAs interlayer that is lattice mismatched with respect to the second solar subcell and having a fourth band gap smaller than the third band gap, wherein the InGaAlAs grading interlayer achieves a transition in lattice constant from the second subcell to the third subcell, and
- a second contact layer below the third solar subcell and making electrical contact therewith.
A method of forming a multijunction solar cell comprising:
- providing a first substrate for epitaxial growth of semiconductor material;
- growing a first solar subcell on the first substrate having a first band gap;
- growing a second solar subcell over the first subcell having a second band gap smaller than the first band gap;
- growing an InGaAlAs grading interlayer over the second solar subcell, wherein the InGaAlAs grading interlayer includes a compositionally step-graded InGaAlAs series of layers, and wherein the InGaAlAs grading interlayer has a constant third band gap greater than the second band gap;
- and
- growing a third solar subcell over the grading interlayer having a fourth band gap smaller than the second band gap such that the third solar subcell is lattice mismatched with respect to the second solar subcell,
- wherein the InGaAlAs grading interlayer achieves a transition in lattice constant from the second solar subcell to the third solar subcell.
Dependencies are inferred from the claim text.