Optical properties of ZnO/GaN/InGaN core-shell nanorods

ZnO/GaN/InGaN core-shell nanorods standing upright in a well defined pattern can be used for sensing applications. As a first step, we grew ZnO nanopillars on top of GaN pyramids resulting in an ordered array of upright ZnO nanorods with average distance of 6 μm and ∼500 nm thickness. This structure was coaxially overgrown with GaN and a subsequent single InGaN quantum well. We report about the different spectral features that are found in these structures. We investigated the various contributions from Zn doping and from the quantum well by spatially resolved cathodoluminescence, transmission electron microscopy, and photoluminescence.