Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 56: Non- and Semi-polar Group-III-Nitrides
HL 56.11: Vortrag
Donnerstag, 25. März 2010, 16:45–17:00, H15
Spectrally resolved cathodoluminescence microscopy of an InGaN SQW on hexagonally inverted GaN pyramids — •Christopher Karbaum1, Frank Bertram1, Sebastian Metzner1, Juergen Christen1, Thomas Wunderer2, and Ferdinand Scholz2 — 1Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — 2Institute of Optoelectronics, University of Ulm, Germany
Three-dimensional self organized hexagonally shaped inverted GaN pyramids with semipolar {1122} facets were grown using MOVPE by applying selective area epitaxy on a two-dimensional pattern of hexagonally shaped SiO2-masks on an optimized c-GaN buffer layer. Subsequently, an InGaN SQW suited for green emission was deposited on the semipolar facets to make use of the reduced QCSE. The spatially-integral spectrum exhibits the near band edge (D0,X) emission of GaN at about 357 nm and an intense broad InGaN luminescence at about 500 nm having a FWHM = 320 meV. The evolution of the (D0,X) luminescence of GaN will be discussed in detail. The InGaN luminescence at the top of the facets is centered at about 535 nm and shifts about 960 meV to shorter wavelengths indicating a strong gradient of the In-concentration. Finally, the InGaN luminescence reaches up to 378 nm close to the (D0,X) luminescence of GaN. Simultaneously the InGaN emission band narrows from FWHM = 235 meV at the top to FWHM = 104 meV above the masks. Furthermore, the temperature-dependence of the InGaN emission energy and the influence of enduring excitation on the InGaN luminescence will be discussed.