Process of growing single crystals of gallium phosphide

A process of producing single crystals of substantially gallium phosphide from a melt containing indium as the solvent, which process comprising heating a mixture of indium, gallium and phosphorus to form a melt and thereafter slowly cooling the melt to room temperature, wherein the melt has an atomic ratio of gallium to phosphorus equal to at least 2.5 to produce said single crystals including at most 0.5 atomic percent of indium.