Heterojunction V-groove multijunction solar cell

Claim 2

A solar energy converter comprising: a first solar cell comprising first multiple p-n heterojunctions in association with a first type of optically active semiconductor material on one side of an insulating substrate; and a second solar cell comprising second multiple p-n heterojunctions in association with a second type of optically active semiconductor material on the opposite side of the insulating substrate; said first type of semiconductor material is GaAlAs, said second type of semiconductor material is Si, and said insulating substrate is semi-insulating GaP.

Claim 3

A solar energy converter comprising: a first solar cell comprising first multiple p-n heterojunctions in association with a first type of optically active semiconductor material A on one side of an insulating substrate; and a second solar cell comprising second multiple p-n heterojunctions in association with a second type of optically active semiconductor material B on the opposite side of the insulating substrate; wherein said material A has an indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with a material A n ' which is doped to n+ type conductivity, has a larger bandgap than A, and is lattice matched to A, the other side of A has a heterojunction with a material A p ' doped to p-type conductivity, and has a larger bandgap than A, and is lattice matched to A; wherein said insulating substrate comprises an insulation layer adjacent to A p ' whose bandgap is greater than or equal to the bandgap of said A material and whose interfaces between said first and second cells are atomically compatible; and wherein said material B has an indirect bandgap less than material A and carrier lifetime limited by Auger recombination, one side of B has a heterojunction with a material B n ' doped to n-type conductivity and lattice matched with B, and the other side of B has a heterojunction with a material B p ' doped to p-type conductivity and lattice matched with B.

Claim 4

A solar energy converter comprising: a first solar cell comprising first multiple p-n heterojunctions in association with a first type of optically active semiconductor material A on one side of an insulating substrate; and a second solar cell comprising second multiple p-n heterojunctions in association with a second type of optically active semiconductor material B on the opposite side of the insulating substrate; wherein said material A has an indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with a material A n ' which is doped to n+ type conductivity, has a larger bandgap than A, and is lattice matched to A, the other side of A has a heterojunction with a material A p ' doped to p-type conductivity, and has a larger bandgap than A, and is lattice matched to A; wherein said insulating substrate comprises an insulation layer adjacent to A p ' whose bandgap is greater than or equal to the bandgap of said A material and whose interfaces between said first and second cells are atomically compatible; and wherein said material B has an indirect bandgap less than material A and carrier lifetime limited by Auger recombination, one side of B has a heterojunction with a material B n ' doped to n-type conductivity and lattice matched with B, and the other side of B has a heterojunction with a material B p ' doped to p-type conductivity and lattice matched with B.

Claim 5

A solar energy converter as set forth in claim 2 wherein: said first material A is Ga 1-x Al x As, A'n is n-Ga 1-y Al y As, A'p is p-Ga 1-y Al 1-y As, said second material B is Si, one side of B has a heterojunction with material B n ' which is n-GaP and is lattice matched with B and the other side of B has a heterojunction with material B p ' which is p-GaP and is lattice matched with B.

Claim 6

A solar energy converter as set forth in claim 3 wherein: said first material A has an indirect bandgap lying lower in energy than its direct bandgap, thereby having a high carrier lifetime and also having high optical absorption of photons slightly greater in energy than said indirect bandgap.

Claim 7

A solar energy converter as set forth in claim 4 wherein said material A is a ternary semiconductor material compound of an indirect bandgap semiconductor material and a direct bandgap semiconductor material.

Claim 8

A solar energy converter as set forth in claim 5 wherein said material A is a group III-V ternary semiconductor material.

Claim 9

A solar energy converter as set forth in claim 6 wherein said first material A is Ga 1-x Al x As and x is approximately 0.5.

Claim 10

A solar energy converter as set forth in claim 6 wherein A is Ga 1-x Al x As and x is 0.4≦×≦0.6.

Claim 11

A solar energy converter comprising: a region of a first semiconductor material, which is responsive to light of a first frequency, having indirect bandgap and being carrier lifetime limited by Auger recombination, and having a first quantity of p-n heterojunctions with semiconductor material which has a larger bandgap than said first material and is lattice matched thereto. a region of a second semiconductor material, which is responsive to light of a second frequency, having indirect bandgap and being carrier lifetime limited by Auger combination and having a second quantity of p-n heterojunctions with a semiconductor material which has a larger bandgap than said second material and is lattice matched thereto, said first quantity of junctions and second quantity of junctions being operable to provide comparable electrical characteristics from the p-n heterojunctions in said first and said second semiconductor materials, said first and second regions being conterminous with and separated by a substrate having electrical isolation properties and being optically transparent at least to light of said second frequency.

Claim 12

A solar energy converter comprising: a region of a first semiconductor material, which is responsive to light of a first frequency, having indirect bandgap and being carrier lifetime limited by Auger recombination, and having a first quantity of p-n heterojunctions with semiconductor material which has a larger bandgap than said first material and is lattice matched thereto. a region of a second semiconductor material, which is responsive to light of a second frequency, having indirect bandgap and being carrier lifetime limited by Auger combination and having a second quantity of p-n heterojunctions with a semiconductor material which has a larger bandgap than said second material and is lattice matched thereto, said first quantity of junctions and second quantity of junctions being operable to provide comparable electrical characteristics from the p-n heterojunctions in said first and said second semiconductor materials, said first and second regions being conterminous with and separated by a substrate having electrical isolation properties and being optically transparent at least to light of said second frequency.

Claim 13

A solar energy converter having a first material A having indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with a material A n ' which is doped to n+ type conductivity, has a larger bandgap than A, and is lattice matched to A, the other side of A has a heterojunction with a material A p ' which is doped to p-type conductivity, has a larger bandgap than A, and is lattice matched to A.

Claim 14

A solar energy converter having a first material A having indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with a material A n ' which is doped to n+ type conductivity, has a larger bandgap than A, and is lattice matched to A, the other side of A has a heterojunction with a material A p ' which is doped to p-type conductivity, has a larger bandgap than A, and is lattice matched to A.

Claim 15

A solar energy converter as set forth in claim 10 wherein said first material A has an indirect bandgap lying lower in energy than its direct bandgap thereby having a high carrier lifetime and also having high optical absorption of photons just slightly greater in energy than said indirect bandgap.

Claim 16

A solar energy converter as set forth in claim 11 wherein said material A is a ternary semiconductor material compound comprised of an indirect bandgap semiconductor material and a direct bandgap semiconductor material.

Claim 17

A solar energy converter as set forth in claim 12 wherein said material A is a group III-V ternary semiconductor material.

Claim 18

A solar energy converter as set forth in claim 13 wherein said first material A is Ga 1-x Al x As and x is approximately 0.5.

Claim 19

A solar energy converter as set forth in claim 13 wherein A is Ga 1-x Al x As and x is 0.4≦×≦0.6.

Claim 20

A solar energy converter having a semiconductor material A with indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with semiconductor material A n doped to n-type conductivity and another side of A has a heterojunction with a semiconductor material A p which is doped to p-type conductivity, said material A n and said material A p having a larger bandgap than said material A.

Claim 21

A solar energy converter having a semiconductor material A with indirect bandgap and carrier lifetime limited by Auger recombination, one side of A has a heterojunction with semiconductor material A n doped to n-type conductivity and another side of A has a heterojunction with a semiconductor material A p which is doped to p-type conductivity, said material A n and said material A p having a larger bandgap than said material A.

Claim 22

A solar energy converter as set forth in claim 16 wherein: said semiconductor material A is silicon, said semiconductor material A n is gallium phosphide doped to n-type conductivity, and said semiconductor material A p is gallium phosphide doped to p-type conductivity.