Abstract: 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.

Abstract: A metamorphic multijunction solar cell having a growth semiconductor substrate with a top surface having a doping in the range of 1x1018 to 1x1020 charge carriers/cm3; 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 ?m to 10 ?m, remains.

Abstract: 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.

Abstract: A method of manufacturing a solar cell comprising: providing a growth substrate depositing on the growth substrate an epitaxial sequence of layers of semiconductor material forming at least a first and second solar subcells depositing a semiconductor contact layer on top of the second solar subcell depositing a reflective metal layer over said semiconductor contact layer such that the reflectivity of the reflective metal layer is greater than 80% in the wavelength range 850 to 2000 nm depositing a contact metal layer composed on said reflective metal layer mounting and bonding a supporting substrate on top of the contact metal layer and removing the growth substrate.

Abstract: A method of manufacturing an inverted metamorphic multijunction solar cell by providing a growth semiconductor substrate with a top surface having a doping in the range of 1×1018 to 1×1020 charge carriers/cm3; depositing a window layer for a top (light facing) subcell subsequently to be formed directly on the top surface of the growth substrate; depositing a sequence of layers of semiconductor material forming a solar cell directly on the window layer; providing a surrogate substrate on the top surface of the sequence of layers of semiconductor material, and removing a portion of the semiconductor substrate so that only the high doped surface portion of the substrate, having a thickness in the range of 0.5 ?m to 10 ?m, remains.