Relationship between misfit-dislocation formation and initial threading-dislocation density in GaInN/GaN heterostructures

The dependence of the critical thickness for the introduction of misfit dislocations in a GaInN/GaN heterostructure system on the dislocation density in the underlying GaN layer was investigated using in situ X-ray diffraction (XRD), ex situ scanning electron microscopy, and transmission electron microscopy analyses. The critical thickness for the introduction of misfit dislocations in the GaInN layer was found to significantly depend on the dislocation density in the underlying GaN layer. Notably, on the basis of the in situ XRD results, a reliable critical thickness for obtaining misfit-dislocation-free growth was determined.