CRYSTAL-GROWTH OF BORON MONOPHOSPHIDE FROM METAL PHOSPHIDE SOLUTIONS

The crystal growth of boron phosphide, BP, has been investigated using two approaches: (i) the addition of phosphorus to a boron-nickel or boron-copper melt, and (ii) the recrystallization of boron phosphide from a nickel phosphide or copper phosphide solution in a temperature gradient. To determine the optimum conditions for the growth processes, the solubility of boron phosphide in nickel phosphide (Ni//1//2P//5) and copper subphosphide (Cu//3P) was determined over a wide temperature range. The solubility of boron phosphide in nickel phosphide was found to be higher than that in copper phosphide. The temperature gradient recrystallization of boron phosphide from nickel phosphide at 1200 C has produced larger crystals. The solution-grown crystals were in the form of hoppers and platelets with platelets dominating. Because of its large energy gap, boron monophosphide has potential applications for high temperature devices and for visible light-emitting devices.