Dresden 2014 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 27: Metamorphic structures: Bringing together incompatible materials II (Joint Focus Session with HL and DS)

DF 27.5: Vortrag

Donnerstag, 3. April 2014, 16:15–16:30, POT 251

Direct correlation of optical and structural properties of InGaN/GaN core-shell microrods by STEM-Cathodoluminescence — •Benjamin Max¹, Marcus Müller¹, Gordon Schmidt¹, Anja Dempewolf¹, Thomas Hempel¹, Peter Veit¹, Frank Bertram¹, Jürgen Christen¹, Martin Mandl², Tilman Schimpke², and Martin Strassburg² — ¹Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — ²OSRAM Opto Semiconductors GmbH, Regensburg, Germany

We present a direct nano-scale correlation of the optical properties with the crystalline real structure of InGaN/GaN core-shell microrods using highly spatially resolved cathodoluminescence spectroscopy (CL). The characterized three microrod samples were grown by MOVPE on c-plane GaN/sapphire template via selective area growth using a SiO₂ mask: a GaN microrod reference structure without shell, a sample with InGaN single quantum well (SQW), and finally a complete core-shell LED structure were investigated. In all samples the GaN NBE emission originates exclusively from the compressively strained GaN template with an emission line at 356 nm. Spatially resolved CL mappings of the undoped sample and the LED structure exhibit luminescence from the InGaN SQW on the non-polar facet at about 400 nm. In contrast, on the semi-polar facet at the tip of the microrod the InGaN SQW luminescence is shifted to longer wavelengths. Additionally, the final core-shell LED structure shows DAP recombination at 380 nm, superimposing the InGaN SQW emission at the non-polar facets.