Influence of substrate miscut angle on surface morphology and luminescence properties of AlGaN

Gunnar Kusch, Haoning Li, Paul R. Edwards, Jochen Bruckbauer, Thomas C. Sadler, Peter J. Parbrook, Robert W. Martin

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Abstract

The influence of substrate miscut on Al0.5Ga0.5 N layers was investigated using cathodoluminescence (CL) hyperspectral imaging and secondary electron imaging in an environmental scanning electron microscope. The samples were also characterized using atomic force microscopy and high resolution X-ray diffraction. It was found that small changes in substrate miscut have a strong influence on the morphology and luminescence properties of the AlGaN layers. Two different types are resolved. For low miscut angle, a crack-free morphology consisting of randomly sized domains is observed, between which there are notable shifts in the AlGaN near band edge emission energy. For high miscut angle, a morphology with step bunches and compositional inhomogeneities along the step bunches, evidenced by an additional CL peak along the step bunches, are observed.
Original languageEnglish
Article number092114
Number of pages4
JournalApplied Physics Letters
Volume104
Issue number9
DOIs
Publication statusPublished - 3 Mar 2014

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Keywords

  • cathodoluminescence
  • III-V semiconductors
  • surface morphology
  • X-ray diffraction

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