NOVELTY - The method comprises epitaxially growing a sacrificial layer upon a separable substrate having a semiconductive composition, epitaxially growing a solar cell portion upon the sacrificial layer, epitaxially growing a stabilizing cell layer of a semiconductor material on the solar cell portion external to III-V multi-junction layers (6), and collectively patterning the solar cell portion and stabilizing cell layer into pattern segments that are separated from each other by a gap (3) extending transversely between the segments to expose an upper portion of the sacrificial layer.    USE - The method is useful for fabricating a multi-junction solar cell on a detachable substrate, where the multi-junction solar cell is a III-V multi-junction solar cell.    ADVANTAGE - The method is capable of economically and reliably fabricating the multi-junction solar cell on the reusable substrate with enhanced structural stability and energy conversion efficiency and high productivity and without any structural defects.    DETAILED DESCRIPTION - The method comprises epitaxially growing a sacrificial layer upon a separable substrate having a semiconductive composition, epitaxially growing a solar cell portion upon the sacrificial layer, epitaxially growing a stabilizing cell layer of a semiconductor material on the solar cell portion external to III-V multi-junction layers (6), collectively patterning the solar cell portion and stabilizing cell layer into pattern segments that are separated from each other by a gap (3) extending transversely between the segments to expose an upper portion of the sacrificial layer, diffusing an etchant material through the gap to the exposed upper portion of the sacrificial layer, and etching to remove the sacrificial layer for releasing the solar cell portion from the substrate. The solar cell portion includes the III-V multi-junction layers. The stabilizing cell layer has a thickness of greater than 5 micrometers that is greater than a thickness of one of the III-V multi-junction layers, and is formed of p-doped and n-doped layers of germanium material. A conductive layer and a metal layer (9a, 9d) are disposed on the stabilizing cell layer of the patterned segments. A carrier (12) is formed collectively over the conductive layers and metal layers of the patterned segments, and has formed in patterned holes, each of which is partially aligned with one of the gap. A conductive contact and a metal contact are formed on an exposed side of the solar cell portion of the patterned segments.    DESCRIPTION OF DRAWING(S) - The figures 2a and 2b show a schematic view of a patterned arrangement of solar cell segments, figure 2c shows a schematic view of individual solar cell segments diced one from the other and figure 2d shows a schematic view of use of an individual solar cell segment.    Gap (3)    Aluminum arsenide layer (4)    Multi-junction III-V semiconductor layers (6)    Metal layer (9a, 9d)    Patterned cell segment (10a)    Carrier. (12)