Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 34: Nitrides: Dots, rods, and structures
HL 34.3: Talk
Tuesday, March 17, 2015, 11:45–12:00, EW 201
Nano-scale-characterization of ordered core-shell GaN micropillars — •Marcus Müller1,2, Gordon Schmidt1, Eduardo Mayolo1, Peter Veit1, Frank Bertram1, Sergiy Krylyuk2,3, Ratan Debnath2,4, Matthew King5, Jong-Yoon Ha2,3, Baomei Wen2,4, Abhishek Motayed2,3,4, Albert Davydov2, and Jürgen Christen1 — 1Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — 2Materials Science and Engineering Division, National Institute of Standards and Technology, USA — 3Institute for Research in Electronics and Applied Physics, University of Maryland, USA — 4N5 Sensors Inc., USA — 5Northrop Grumman ES, USA
In this study we report on the approach of combining top-down principle and the bottom-up processes to fabricate ordered core-shell GaN micropillars. The overgrowth of inductively coupled plasma etched GaN pillars by hydride vapor phase epitaxy produces hexagonally shaped micropillars with vertical non-polar sidewalls and top facet truncated by highly vicinal facets. Scanning electron microscopy measurements of the samples reveal a homogeneous growth. The strain tensors at selected regions of micropillars were analysed, using electron-backscattered-diffraction. Direct correlation of the optical and structural properties of the core-shell GaN micropillars has been achieved using highly spatially resolved cathodoluminescence spectroscopy. CL mappings of the MOVPE grown GaN-bulk template, and the etched core-shell GaN heterostructures reveal a distinct blue-shift of the donor-bound exciton emission due to a strain relaxation.