Gallium arsenide
Dual junction cells can be made on Gallium arsenide wafers. Alloys of Indium gallium phosphide in the range In.5Ga.5P through In.53Ga.47P serve as the high band gap alloy. This alloy range provides for the ability to have band gaps in the range 1.92–1.87eV. The lower GaAs junction has a band gap of 1.42eV.