Epitaxial InGaN with an In content of up to 89% was grown on a GaN template on a sapphire substrate using metalorganic chemical vapor deposition. The grown layer showed a bilayered structure of In- and Ga-rich InGaN parallel to the growth plane, as confirmed by both x-ray diffraction and electron microscopy. High-angle annular dark-field images revealed that pyramidal Ga-rich InGaN had formed on the top of the In-rich InGaN layer with an abrupt interface. Nucleation of the In-rich InGaN was believed to be related to threading dislocations stemming from the GaN buffer layer.
- Phase separation