Abstract: A multijunction solar cell includes an upper first solar subcell having a first band gap, a second solar subcell having a second band gap smaller than the first band gap, and a first graded interlayer composed of (InxGa1-x)yAl1-yAs adjacent to the second solar subcell. The first graded interlayer has a third band gap greater than the second band gap subject to the constraints of having the in-plane lattice parameter greater or equal to that of the second subcell and less than or equal to that of the third subcell, wherein 0<x<1 and 0<y<1, and x and y are selected such that the band gap of the first graded interlayer remains constant throughout its thickness at 1.5 eV. A third solar subcell is adjacent to the first graded interlayer and has a fourth band gap smaller than the second band gap such that the third subcell is lattice mismatched with respect to the second subcell.

Abstract: A multijunction solar cell includes an upper first solar subcell, a second solar subcell adjacent to the first solar subcell, a third solar subcell adjacent to the second solar subcell, and a graded interlayer adjacent to the third solar subcell. The graded interlayer has a band gap that is greater than the band gap of the third solar subcell and is composed of a compositionally step-graded series of (InxGa1-x)yAl1-yAs layers with monotonically changing lattice constant, with x and y having respective values such that the band gap of the graded interlayer remains constant throughout its thickness, and wherein 0<x<1 and 0<y<1. A fourth solar subcell is adjacent to the graded interlayer and is lattice mismatched with respect to the third solar subcell. The graded interlayer provides a transition in lattice constant from the third solar subcell to the fourth solar subcell. A lower fifth solar subcell is adjacent to the fourth solar subcell.

Abstract: A transfer substrate with a compliant resin is used to bond one or more chips to a target wafer. An implant region is formed in a transfer substrate. A portion of the transfer substrate is etched to form a riser. Compliant material is applied to the transfer substrate. A chip is secured to the compliant material, wherein the chip is secured to the compliant material above the riser. The chip is bonded to a target wafer while the chip is secured to the compliant material. The transfer substrate and compliant material are removed from the chip. The transfer substrate is opaque to UV light.

Abstract: A multijunction solar cell includes an upper first solar subcell having a first band gap, a second solar subcell having a second band gap smaller than the first band gap, and a first graded interlayer composed of (InxGa1-x)yAl1-yAs adjacent to the second solar subcell. The first graded interlayer has a third band gap greater than the second band gap subject to the constraints of having the in-plane lattice parameter greater or equal to that of the second subcell and less than or equal to that of the third subcell, wherein 0<x<1 and 0<y<1, and x and y are selected such that the band gap of the first graded interlayer remains constant throughout its thickness at 1.5 eV. A third solar subcell is adjacent to the first graded interlayer and has a fourth band gap smaller than the second band gap such that the third subcell is lattice mismatched with respect to the second subcell.

Abstract: A multijunction solar cell includes an upper first solar subcell, a second solar subcell adjacent to the first solar subcell, a third solar subcell adjacent to the second solar subcell, and a graded interlayer adjacent to the third solar subcell. The graded interlayer has a band gap that is greater than the band gap of the third solar subcell and is composed of a compositionally step-graded series of (InxGa1-x)y Al1-yAs layers with monotonically changing lattice constant, with x and y having respective values such that the band gap of the graded interlayer remains constant throughout its thickness, and wherein 0<x<1 and 0<y<1. A fourth solar subcell is adjacent to the graded interlayer and is lattice mismatched with respect to the third solar subcell. The graded interlayer provides a transition in lattice constant from the third solar subcell to the fourth solar subcell. A lower fifth solar subcell is adjacent to the fourth solar subcell.

Abstract: A multijunction solar cell having at least four solar subcells includes a first solar subcell having a first band gap. A first graded interlayer adjacent to the first solar subcell and has a second band gap greater than the first band gap and that is constant at 1.5 eV throughout the thickness of the first graded interlayer. A second solar subcell is adjacent to the first graded interlayer and has a third band gap smaller than the first band gap of the first solar subcell. The second solar subcell is lattice mismatched with respect to the first solar subcell. A second graded interlayer is adjacent to the second solar subcell and has a fourth band gap greater than the third band gap of the second solar subcell and that is constant at 1.1 eV throughout the thickness of the second graded interlayer. A third solar subcell is adjacent to the second graded interlayer and has a fifth band gap smaller than the third band gap of the second solar subcell.

Abstract: A transfer substrate with a compliant resin is used to bond one or more chips to a target wafer. An implant region is formed in a transfer substrate. A portion of the transfer substrate is etched to form a riser. Compliant material is applied to the transfer substrate. A chip is secured to the compliant material, wherein the chip is secured to the compliant material above the riser. The chip is bonded to a target wafer while the chip is secured to the compliant material. The transfer substrate and compliant material are removed from the chip. The transfer substrate is opaque to UV light.

Abstract: A multijunction solar cell having at least four solar subcells includes a first solar subcell having a first band gap, and a first graded interlayer adjacent to the first solar subcell, wherein the first graded interlayer has a second band gap greater than the first band gap and that is constant at 1.5 eV throughout the thickness of the first graded interlayer. A second solar subcell is adjacent to the first graded interlayer, wherein the second solar subcell has a third band gap smaller than the first band gap of the first solar subcell and wherein said second solar subcell is lattice mismatched with respect to the first solar subcell. A second graded interlayer is adjacent to the second solar subcell, wherein the second graded interlayer has a fourth band gap greater than the third band gap of the second solar subcell and that is constant at 1.1 eV throughout the thickness of the second graded interlayer.

Abstract: A transfer substrate with a compliant resin is used to bond one or more chips to a target wafer. An implant region is formed in a transfer substrate. A portion of the transfer substrate is etched to form a riser. Compliant material is applied to the transfer substrate. A chip is secured to the compliant material, wherein the chip is secured to the compliant material above the riser. The chip is bonded to a target wafer while the chip is secured to the compliant material. The transfer substrate and compliant material are removed from the chip. The transfer substrate is opaque to UV light.

Abstract: A multijunction solar cell including an upper first solar subcell, and the base-emitter junction of the upper first solar subcell being a homojunction; a second solar subcell adjacent to said first solar subcell; a third solar subcell adjacent to said second solar subcell. A first graded interlayer is provided adjacent to said third solar subcell. A fourth solar subcell is provided adjacent to said first graded interlayer, said fourth subcell is lattice mismatched with respect to said third subcell. A second graded interlayer is provided adjacent to said fourth solar subcell; and a lower fifth solar subcell is provided adjacent to said second graded interlayer, said lower fifth subcell is lattice mismatched with respect to said fourth subcell.

Abstract: A multijunction solar cell including an upper first solar subcell, and the base-emitter junction of the upper first solar subcell being a homojunction; a second solar subcell adjacent to said first solar subcell; a third solar subcell adjacent to said second solar subcell. A first graded interlayer is provided adjacent to said third solar subcell. A fourth solar subcell is provided adjacent to said first graded interlayer, said fourth subcell is lattice mismatched with respect to said third subcell. A second graded interlayer is provided adjacent to said fourth solar subcell; and a lower fifth solar subcell is provided adjacent to said second graded interlayer, said lower fifth subcell is lattice mismatched with respect to said fourth subcell.