TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method further comprises removing a portion of the support structure thus reducing the weight of the support structure after removing the growth semiconductor substrate. The support structure is formed by adhering a thin sheet to a rigid member using a non-permanent adhesive such that the rigid member is detachable from the thin sheet after the support substrate is bonded to the lower subcell and the growth semiconductor substrate is removed.Forming the upper subcell comprises growing GaxIn1-xP semiconductor material over the semiconductor growth substrate. Forming the middle subcell comprises growing InyGa1-yAs semiconductor material. Forming the lower subcell comprises depositing InyGa1-yAs semiconductor material over the middle subcell. Forming the lower subcell comprises depositing Si(x)Ge(1-x) semiconductor material over the middle subcell. Forming grading layers between the lower subcell and the middle subcell comprises growing InyGa1-yAs to reduce stress in the lower subcell resulting from mismatch of lattice spacing. The semiconductor growth substrate is removed by etching the substrate.Preferred Parameter: The lattice-mismatch between the lower subcell and the growth substrate is at least1% (preferably at least5%).Preferred Material: The substrate is gallium arsenide, germanium, indium phosphide, or silicon substrate.Preferred Component: The lower subcell and the middle subcell comprise indium-gallium-arsenide based material and the upper subcell comprises indium-gallium-phosphide based material.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The support structure comprises a plastic sheet having a top and bottom.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The support structure comprises a metal wafer having a reflective optical coating formed to provide increased optical reflectance.Preferred Parameter: The metal surface across the lateral spatial extent of the support structure has a reflectivity of at least 90% (preferably at least 95%).