Cathodoluminescence and Al composition of biaxially stressed AlGaN/GaN epitaxial layers

In Hwan Lee, Y. Park

Research output: Contribution to journalConference article

10 Citations (Scopus)

Abstract

We report on the cathodoluminescence (CL) of Al0.25Ga0.75N (x = 0.25-) and underlying GaN films and on the Al composition of the AlGaN with the biaxial residual stress taken into account. Crack-free thick AlGaN layers were fabricated by introducing a thin AlN interlayer on a high quality GaN epitaxial layer. The CL band-edge emission of AlGaN from a non-cracked region appeared at a lower energy than that from the cracked region. This is the direct indication, that crack relaxes biaxial tensile stress in AlGaN layers. When the Al composition x was lower than 0.5, the Al compositions measured by X-ray diffraction fell between the values estimated by Vegard's law and the values of pseudomorphic assumption due to partially relaxed residual stress in the AlGaN films. When x > 0.5, they are in agreement with Vegard's law, indicating that the AlGaN layer is fully relaxed.

Original languageEnglish
Pages (from-to)67-71
Number of pages5
JournalPhysica Status Solidi (A) Applied Research
Volume192
Issue number1
DOIs
Publication statusPublished - 2002 Jul
Event4th International Symposium on Blue Lasers and Light Emitting Diodes (ISBLLED-2002) - Cordoba, Spain
Duration: 2002 Mar 112002 Mar 15

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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