Ammonothermal Crystal Growth of Indium Nitride

Abstract

InN crystals with hexagonal shapes were grown from InCl3 and KNH2 in supercritical ammonia at around 280 MPa. For a successful crystal growth a molar ratio of the chloride to the amide of 1:3 was applied, thus providing an essentially ammononeutral milieu. The obtained InN crystals vary in size and aspect ratio depending on the applied furnace temperature: at 663 K hexagonal platelets up to 2 μm in diameter, as well as rods with lengths of 4 μm and diameters of 1 μm were obtained; at 773 K rods grew up to 2.5 μm in length. By combining both temperature programs, with a 10 h annealing step at both temperatures, we were able to increase the crystal size up to 5.2 μm in length and 0.4 μm in diameter.