We report on the growth and characterization of microscale GaN structures selectively grown on the apexes of hexagonal GaN pyramids. SiO 2 near the apex of the hexagonal GaN pyramids was removed by an optimized photolithography process and subsequently subjected to selective growth of micro scale GaN structures by metal organic vapor phase epitaxy (MOVPE). The pyramidal GaN microstructures which have semi-polar f1101g facets, were formed only on the apexes of lower GaN pyramids. The size of the selectively grown micro GaN structures was easily controlled by the growth time. Reduction of the threading dislocation density was confirmed by transmission electron microscopy (TEM) in the selectively regrown micro GaN structures. However, stacking faults developed near the edge of the SiO 2 film because of the roughness and nonuniform thickness of the SiO 2 film. #

No abstract

No abstract

No abstract

We determined the effect of the type of substrate on the growth of InGaN nanostructures by mixed-source hydride vapor phase epitaxy (HVPE). InGaN nanostructures were formed on c-plane, r-plane sapphire, and undoped GaN substrates at various growth temperatures. Also, we looked into the changes in the structural and optical characteristics of InGaN nanostructures when antimony (Sb) is used as a surfactant during the growth of InGaN nanostructures. The samples were characterized by scanning electron microscopy (SEM) and photoluminescence (PL) measurement. The density of the nanostructures on the surface and the indium composition of the InGaN layer varied depending on the type of substrate and growth temperature. The aligning direction of the nanostructures markedly changed and the indium composition increased when Sb was used as the surfactant during the growth of the InGaN nanostructure, compared with the results of the InGaN nanostructures grown without Sb addition.