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Keywords:

  • alloy fluctuations;
  • cathodoluminescence;
  • InGaN;
  • growth;
  • morphology

Abstract

The origin of indium fluctuations in indium-rich quantum wells (QWs) is of high interest for direct green laser diodes. We present the correlation of morphological features such as macrosteps investigated by AFM measurements and wavelength fluctuations seen in cathodoluminescence images of InGaN/GaN QWs grown by metal organic vapor phase epitaxy. We observe an opposed wavelength shift of 5 nm in the vicinity of macrosteps for the investigated UV and green InGaN QW samples. We present a growth model taking adsorption, desorption, and migration processes into account to explain this difference via a temperature dependent change in indium incorporation in the vicinity of the observed macrostep edges.