Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 62: Gallium Nitride: Optical and Electronic Properties

HL 62.12: Vortrag

Mittwoch, 9. März 2016, 18:00–18:15, H17

Nanoscale (in)homogeneities of a thick In_0.2Ga_0.8N layer grown on high quality bulk GaN substrate — •Max Trippel¹, Gordon Schmidt¹, Peter Veit¹, Sebastian Metzner¹, Thomas Hempel¹, Silke Petzold¹, Frank Bertram¹, Marlene Glauser², Lise Lahourcade², Raphaël Butté², Jean-François Carlin², Nicolas Grandjean², and Jürgen Christen¹ — ¹Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — ²Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, Switzerland

InGaN alloys have received much attention for their successful use as active layers for optoelectronic applications. Despite considerable progress in the understanding of this material system the growth of high quality thick InGaN layers is still a challenge due to relaxation and compositional inhomogeneities.

We report on the inhomogeneities of a thick In_0.2Ga_0.8N layer on nanometerscale using transmission electron microscopy combined with cathodoluminescence spectroscopy (STEM-CL) at 15 K.

A nominally 100 nm thick InGaN layer on top of a 1 µm GaN buffer was grown by metal-organic chemical vapor phase epitaxy (MOVPE) on a high quality free standing GaN pseudo substrate. (S)TEM images show two different regions on the surface: planar areas as well as regions of three dimensional growth. Highly spatially resolved STEM-CL mappings performed at 15 K reveal dominant luminescence at about 465 nm within planar regions and strong inhomogeneities of the InGaN emission in the regions of three dimensional growth.