Strain influenced indium composition distribution in GaN/InGaN core-shell nanowires

The optical properties, indium concentration and distribution, defect morphology, and strain distribution of GaN/InGaN coaxial nanowires grown by metal organic chemical vapor deposition were investigated using spatially resolved cathodoluminescence, scanning transmission electron microscopy, and finite element analysis. The results indicate that InGaN layers with 40% or greater indium incorporation and low defect density can be achieved. The indium distribution in the InGaN shell layer was measured and qualitatively correlated with the calculated strain distribution. The three-dimensional compliance of the GaN nanowire leads to facile strain relaxation in the InGaN heteroepitaxial layer, enabling high indium incorporation and high crystalline quality. (C) 2010 American Institute of Physics. [doi:10.1063/1.3513345]