Growth and decomposition of bulk GaN: role of the ammonia/nitrogen ratio

Cathodoluminescence evaluation of subsurface damage in GaN substrate after polishing

“…The increase in roughness may be due to a slight surface decomposition during the annealing. Shin et al reported that GaN crystals showed significant surface roughening after the annealing with pure ammonia at 1130 °C for 2 hours [12]. The surface roughening after ammonia annealing may be due to the reaction between GaN and the Hcontaining species which were decomposed from NH 3 .…”

Growth and characterization of millimeter-sized GaN crystals by carbothermal reduction and nitridation of Ga2O3

“…Laue photos showed this bar crystal to have grown along the [1 1 0] direction. The growth rate of this crystal along the [1 1 0] direction was very fast (0.5-1.5 mm h À1 ) compared with that of crystals grown by other vapor methods ($25 mm h À1 [22]). This fast growth probably caused by the high-Ga 2 O concentration at the tube outlet for Ga 2 O vapor and high temperature of 1200 1C.…”

“…The growth of 1090-1200 1C considerably decreased the number of crystals at 120 min while this growth time enlarged the crystal size. It is reported that high temperatures facilitate the decomposition of NH 3 to H-containing compounds (H 2 , NH and NH 2 ) [22]. For the 120 min growth at 1090-1200 1C, it is thus assumed that these H-containing species readily decompose small GaN crystals with high surface energy and a limited number of crystals grow to larger crystals with stable surfaces.…”

Synthesis of nanocrystalline aluminum–gallium nitride (AlxGa1−xN; x = 0.1 to 0.5) with oxide precursors via ammonolysis

“…23,24 Phase separation seems to be partially suppressed for specimen synthesized via the alkoxide route with improved cross-linking of the Ga-and Al-alkoxide precursors. For this case, it appears that the increased mobility of the components causes segregation and eventually phase separation through an evaporation/condensation mechanism as previously proposed.…”