Generation of misfit dislocations in high indium content InGaN layer grown on GaN

We have investigated the relaxation of the misfit strain by the formation of misfit dislocations and stacking faults in high indium content In_xGa_1-xN layers grown by metal-organic chemical vapor deposition. The misfit dislocations in the highly mismatched In_0.33Ga_0.66N/GaN system are generated not only at the InGaN/GaN interface but also within an InGaN layer. It indicates that the InGaN layer in the interface is partially relaxed and the considerable residual strain is relaxed within the InGaN layer. In addition, we observed that stacking faults formed by stacking order mismatch between sub-grains play the role of a seed in the formation of misfit dislocations within a high indium content In_xGa_1-xN layer.