A solar cell comprising an epitaxial sequence of layers of semiconductor material thrilling at least a first and second solar subcells; a semiconductor contact layer disposed on the bottom surface of the second solar subcell; a reflective metal layer disposed below the semiconductor contact layer such that the reflectivity of the reflective metal layer is greater than 80% in the wavelength range 850 to 2000 nm, for reflecting light back into the second solar subcell.

A four junction solar cell and its method of manufacture including an upper first solar subcell composed of a semiconductor material 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 graded interlayer adjacent to the third solar subcell and having a fourth band gap greater than the third band gap; and a bottom solar subcell adjacent to the graded interlayer and being lattice mismatched from the third solar subcell and having a fifth band gap smaller than the fifth band gap, wherein the selection of composition of the subcells and their band gaps maximizes the efficiency of the solar cell at a predetermined temperature value (between 28 and 70 degrees Centigrade) at a predetermined time after the initial deployment in space, (the time of the initial deployment being referred to as “beginning-of-life (BOL)”), such predetermined time being referred to as the “end-of-life (EOL)” time, and such time being at least one year.

A multijunction solar cell assembly and its method of manufacture including interconnected first and second discreate semiconductor body subassemblies disposed adjacent and parallel to each other, in the sense of the incoming illumination, each semiconductor body subassembly including first top subcell, and possibly third middle subcells and a bottom solar subcell; wherein the interconnected subassemblies form at least a Three junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor body with its at least least two junctions and the bottom solar subcell in the second semiconductor body representing the additional junction.

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 directly below and adjacent to the upper first solar subcell, and having a second band gap smaller than said first band gap; wherein a light scattering layer is provided below the upper first solar subcell and adjacent to the upper first solar subcell for redirecting the incoming light to be scattered along longer path lengths into the second solar subcell.

The present disclosure relates to a method for manufacturing a device, where the device includes, in order, a metamorphic contact layer, a first metamorphic junction, a metamorphic tunnel junction, and a second metamorphic junction. To produce the device, the manufacturing includes, in order, a first depositing of a buffer layer onto a substrate, a second depositing of the metamorphic contact layer, a third depositing of the first metamorphic junction, a fourth depositing of the metamorphic tunnel junction, a fifth depositing of the second metamorphic junction, and the removing of the buffer layer and the substrate.

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 at least one of the solar cells has a graded band gap throughout its thickness.

A multijunction solar cell comprising a first solar subcell having a first band gap; a second solar subcell disposed adjacent to said first solar subcell and including an emitter layer, and a base layer having a second band gap less than the first band gap, and being lattice mismatched with the upper first solar subcell, and an intermediate layer directly adjacent to and disposed between first and the second solar subcells and compositionally graded to lattice match the first solar subcell on one side and the second solar subcell on the other side, and arranged so that light can enter and pass through the first solar subcell and at least a portion of which can be reflected back into the first solar subcell by the intermediate layer, and is composed of a plurality of layers of materials with discontinuities in their respective indices of refraction.

A stacked multi-junction solar cell with a first subcell having a top and a bottom, and with a second subcell. The first subcell is implemented as the topmost subcell so that incident light first strikes the top of the first subcell and after that strikes the second subcell through the bottom. A first tunnel diode is arranged between the bottom of the first subcell and the second subcell. A window layer is arranged on the top of the first subcell, and the band gap of the window layer is larger than the band gap of the first subcell. A cover layer is arranged below metal fingers and above the window layer, and an additional layer is arranged below the cover layer and above the window layer. A thickness of the additional layer is less than the thickness of the window layer.

A metamorphic multijunction solar cell having a growth semiconductor substrate with a top surface having a doping in the range of 1x10.sup.18 to 1x10.sup.20 charge carriers/cm.sup.3; a window layer for a top (light facing) subcell formed directly on the top surface of the growth substrate; a sequence of layers of semiconductor material forming a solar cell directly on the window layer; a surrogate substrate on the top surface of the sequence of layers of semiconductor material, wherein a portion of the semiconductor substrate is removed so that only the high doped surface portion of the substrate, having a thickness in the range of 0.5 μm to 10 μm, remains.

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 at least one of the solar cells has a graded band gap throughout its thickness.