Morphology Control ofHot-Wall MOCVD Selective AreaGrown Hexagonal GaN Pyramids.

Morphological variations of gallium polar (0001)-orientedhexagonalGaN pyramids grown by hot-wall metal organic chemical vapor depositionunder various growth conditions are investigated. The stability ofthe semipolar {11̅02} and nonpolar {11̅00} facets is particularlydiscussed. The presence of the {11̅02} facets near the apexof the pyramid was found to be controllable by tuning the absoluteflow rate of ammonia during the growth. Vertical nonpolar {11̅00}facets appeared in gallium-rich conditions, which automatically werecreated when the growth time was prolonged beyond pyramid completion.The result was attributed to a gallium passivation of the {11̅00}surface. [ABSTRACT FROM AUTHOR]