Methods for fabricating thin film III-V compound solar cell

A plurality of thin film multi-junction solar cells free of a six inch GaAs substrate on which the plurality of solar cells were formed, each comprising:

• a first active layer including InGaAs forming a first junction;
• a second active layer including GaAs or a compound comprising Ga and As forming a second junction;
• a third active layer forming a third junction, at least one of the first active layer, second active layer or third active layer having a lattice mismatch with the six inch GaAs substrate on which the active layers were grown;
• and
• a support backing layer formed directly on the first active layer of each of the plurality of solar cells providing a common support for the plurality of solar cells, the support backing layer having an area corresponding to the six inch GaAs substrate, the support backing layer comprising a plurality of metal sublayers including a main support sublayer comprising nickel, the support backing layer providing structural support for each of the plurality of solar cells in an absence of the six inch GaAs substrate, wherein each of the plurality of thin film multi-junction solar cells is flexible.