Growth and optical characterization of GaN nanorods covered with InGaN multiple quantum wells

The tunable and direct band gab, ranging from 3.4 eV (GaN) to 0.7 eV (InN) depending on the indium content, makes InGaN interesting for high efficient optoelectronic devices in the visible spectra of the light. However strain between the substrate, such as sapphire or silicon, and the InGaN layer causes defects in the lattice which reduce the optical performance of the material. An advantage of nanorods compared to 2D layer is that the extent of those strain compensating lattice defects is smaller due to elastic strain relaxation at the free surfaces of the nanorods. In this talk the self-organized, and therefore mask-free, growth of core-shell nanorods by metal-organic vapor phase epitaxy on (0001) sapphire will be presented. The optical properties of the nanorods, consisting of a GaN core and a shell of InGaN multiple quantum wells, have been characterized by cathodoluminescence.