Quantitative evaluation of the atomic structure of defects and composition fluctuations at the nanometer scale inside InGaN/GaN heterostructures

Investigation is carried out by high-resolution electron microscopy on threading dislocations using data treatments with procedures that allow the extraction of the most likely atomic configurations. We also report In composition fluctuations inside InGaN/GaN quantum wells by coupling HRTEM, image simulation and Finite Element Modelling (FEM) of the thin foil relaxation. The results show that the indium content may be close to x = 1.0 in the clusters and this is much higher that was previously suggested by 2D FEM modelling.