title: Nanofocus x-ray diffraction and cathodoluminescence investigations into individual core-shell (In,Ga)N/GaN rod light-emitting diodes.
abstract: Employing nanofocus x-ray diffraction, we investigate the local strain field induced by a five-fold (In,Ga)N multi-quantum well embedded into a GaN micro-rod in core-shell geometry. Due to an x-ray beam width of only 150 nm in diameter, we are able to distinguish between individual m-facets and to detect a significant in-plane strain gradient along the rod height. This gradient translates to a red-shift in the emitted wavelength revealed by spatially resolved cathodoluminescence measurements. We interpret the result in terms of numerically derived in-plane strain using the finite element method and subsequent kinematic scattering simulations which show that the driving parameter for this effect is an increasing indium content towards the rod tip.
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Krause
authors.forename: Michael
authors.initials: M
authors.lastname: Hanke
authors.forename: Zongzhe
authors.initials: Z
authors.lastname: Cheng
authors.forename: Michael
authors.initials: M
authors.lastname: Niehle
authors.forename: Achim
authors.initials: A
authors.lastname: Trampert
authors.forename: Martin
authors.initials: M
authors.lastname: Rosenthal
authors.forename: Manfred
authors.initials: M
authors.lastname: Burghammer
authors.forename: Johannes
authors.initials: J
authors.lastname: Ledig
authors.forename: Jana
authors.initials: J
authors.lastname: Hartmann
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.forename: Hergo-Heinrich
authors.initials: HH
authors.lastname: Wehmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Waag