GROWTH OF GALLIUM ORTHOPHOSPHATE SINGLE-CRYSTALS IN ACIDIC HYDROTHERMAL SOLUTIONS

The hydrothermal growth of GaPO4 single crystals has been studied in several solutions. Among many solutions, H3PO4, HCl and H2SO4 solutions were found to be effective solvents for the growth of GaPO4 single crystals. Single crystals have been hydrothermally grown at temperatures over the range 210 to 290-degrees-C in these solutions with seed crystals. HCl solution was found to be the most effective solvent in which to grow large single crystals. Morphologies of crystals grown at temperatures below 200-degrees-C tended to be bounded by small major rhombohedral (1 0 1BAR 1) faces. In the temperature range from 210 to 430-degrees-C, the crystals have morphologies bounded by prism (1 0 1BAR 0), small major rhombohedral (1 0 1BAR 1) and minor rhombohedral (0 1 1BAR 1) faces, and grew with well developed basal (0 0 0 1) faces with increase in the growth temperature. Single crystals of GaPO4 with lower dislocation density have been hydrothermally grown at 210 to 290-degrees-C in 3 M H3PO4 solution.