Morphology control of hot-wall MOCVD selective area grown hexagonal GaN pyramids

摘要

Morphological variations of gallium polar (0001)-oriented hexagonal GaN pyramids grown by hot-wall metal organic chemical vapor deposition under various growth conditions are investigated. The stability of the semipolar {11?02} and nonpolar {11?00} facets is particularly discussed. The presence of the {11?02} facets near the apex of the pyramid was found to be controllable by tuning the absolute flow rate of ammonia during the growth. Vertical nonpolar {11?00} facets appeared in gallium-rich conditions, which automatically were created when the growth time was prolonged beyond pyramid completion. The result was attributed to a gallium passivation of the {11?00} surface.