Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first back contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A method of fabricating a four junction solar cell by identifying the composition and band gaps of the upper first, second and third subcells that maximizes the efficiency of the solar cell at a predetermined time after initial deployment by simulation; fabricating one or more four-junction test solar cells in accordance with the identified composition and band gaps of the upper first, second and third subcells; performing one or more optical or electrical tests on the fabricated one or more four-junction test solar cells; based on results of the tests, determining one or more properties of at least one of the upper first, second or third subcells to be modified in subsequent fabrication of four-junction solar cells, including the band gap, doping level and profile, and thickness of each of the subcell layers; and fabricating a further four-junction solar cell in accordance with the modified properties of at least one of the upper first, second or third subcells to optimize the efficiency of the solar cell at

Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first hack contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell around the periphery of the multijunction solar sell that lies in the path of the incoming light beam.

Abstract: A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell that lies in the path of the incoming light beam.

Abstract: A method of fabricating a four junction solar cell having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; and a fourth solar subcell adjacent to and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first hack contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A method of fabricating four junction solar cell wherein the selection of the composition of the subcells and their band gaps maximizes the efficiency at high temperature (in the range of 50 to 100 degrees Centigrade) in deployment in space at a specific predetermined time after initial deployment (referred to as the beginning of life or BOL), such predetermined time being referred to as the end-of-life (EOL), and being at least five years after the BOL, such selection being designed not to maximize the efficiency at BOL but to increase the solar cell efficiency at the EOL while disregarding the soar cell efficiency achieved at the BOL, such that the solar cell efficiency designed at the BOL is less than the solar cell efficiency at the BOL that would be achieved if the selection were designed to maximize the solar cell efficiency at the BOL.

Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first back contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell that lies in the path of the incoming light beam.

Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first back contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first back contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.

Abstract: A multijunction solar cell and its method of fabrication, having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; a first and second DBR structure adjacent to the third solar subcell; and a fourth solar subcell adjacent to the DBR structures and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

Abstract: A multijunction solar cell and its method of fabrication, having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; a first and second DBR structure adjacent to the third solar subcell; and a fourth solar subcell adjacent to the DBR structures and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

Abstract: A multijunction solar cell comprising at least a first subcell and a second subcell, a first alpha layer disposed over said first solar subcell grown using a surfactant and dopant including selenium or tellurium, the first alpha layer configured to prevent threading dislocations from propagating; a metamorphic grading interlayer disposed over and directly adjacent to said first alpha layer; a second alpha layer grown using a surfactant and dopant including selenium or tellurium over and disposed directly adjacent to said grading interlayer to prevent threading dislocations from propagating; wherein the second solar subcell is disposed over said grading interlayer such that the second solar subcell is lattice mismatched with respect to the first solar subcell.

Abstract: A method of forming a multijunction solar cell comprising at least a first subcell and a second subcell, the method including forming a first alpha layer over said first solar subcell using a surfactant and dopant including selenium or tellurium, the first alpha layer configured to prevent threading dislocations from propagating; forming a metamorphic grading interlayer over and directly adjacent to said first alpha layer; forming a second alpha layer using a surfactant and dopant including selenium or tellurium over and directly adjacent to said grading interlayer to prevent threading dislocations from propagating; and forming the second solar subcell over said grading interlayer such that the second solar subcell is lattice mismatched with respect to the first solar subcell.

Abstract: A multijunction solar cell and its method of fabrication, having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; a first and second DBR structure adjacent to the third solar subcell; and a fourth solar subcell adjacent to the DBR structures and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

Abstract: A flexible solar cell assembly and methods for its manufacture are described. The flexible solar cell assembly comprises: solar cells comprising opposing top and back surfaces of different polarities, a contact at the top surface and a contact at the back surface; a flexible substrate; and conductive traces having end portions bonded to the top and bottom contacts of different solar cells so as to interconnect them in electrical series.

Abstract: A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell that lies in the path of the incoming light beam.