Growth of cubic GaN crystals from hexagonal GaN feedstock

Structure of nanocrystalline ammonothermal GaN in dependence of temperature and type of acidic mineralizer

“…This is consistent with previous report [18,24] that using NH 4 Br and NH 4 I to enhance the formation of c-GaN. It is indicated that GaN phase relations were also influenced by the different types of acidic mineralizers, and could be controlled by choosing an appropriate acidic mineralizer and growth temperature (Fig.…”

“…4a-c). Samples prepared with NH 4 Cl at temperature of 500 1C, or with NH 4 Br and NH 4 I at temperatures between 400 and 450 1C exhibited the band at a range of 552-555 cm À1 that could be identified as phonon modes of c-GaN [24] (Fig. 4a-c).…”

Low-temperature solvothermal synthesis of nanocrystalline indium nitride and Ga–In–N composites from the decomposition of metal azides

“…22 Note that in supercritical ammonia synthesis of GaN, cubic phase formation is favored when halide salt additives are present, thus a halide influence may also be applicable in the present syntheses. 23 When the hexadecane reaction was run at solvent reflux temperatures (y290 uC), trace In metal was observed in the XRD spectrum that may be due to the glass reactor walls being y10 uC hotter than the solution and leading to decomposition of the thermally metastable InN. Inert TG-DTA shows that the InN produced in this work begins to decompose near 400 uC, which agrees with bulk InN thermal stability.…”

Temperature effect of ammonium halogenides as mineralizers on the phase stability of gallium nitride synthesized under acidic ammonothermal conditions

“…DG = 1.31 kJ mol 21 at 800 K. The DG value increases only slightly upon further temperature increase, which seems to support the occurrence of the oftenobserved mixed phases in self-nucleated GaN. 26,28,29 The phase determining conditions are therefore kinetically rather than thermodynamically driven, 30 suggesting that phase stabilization should be easy to achieve, e.g. upon proper choice of a single-crystalline substrate.…”