A comparative study of high resolution transmission electron microscopy, atomic force microscopy and infrared spectroscopy for GaN thin films grown on sapphire by metalorganic chemical vapor deposition

Zhe Chuan Feng*, Kun Li, Yun Tian Hou, Jie Zhao, W. Lu, W. E. Collins

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A comparative study of GaN grown on sapphire by metalorganic chemical vapor deposition (MOCVD) is performed by transmission electron microscopy (TEM), atomic force microscopy (AFM) and infrared reflectance. A correlation between the microstructure features revealed by TEM/AFM and optical characteristics obtained from infrared reflectance is explored. TEM observations reveal the GaN epilayers with high densities of threading dislocations. Dislocations in the undoped GaN tend to form open core structures, while dislocation lines in the Si-doped GaN are sharper and the strain contrast is much more discrete. Also the GaN buffer layer grown at low temperature is found to transform into the thermodynamically stable wurtzite structure during high temperature post-buffer GaN growth. The infrared reflectance shows the corresponding behavior. The interference fringes of the Si doped sample were observed with the reflectance reduction and contrast damping, which can be interpreted by the presence of a transition/defect layer near the interface of GaN/sapphire.

Original languageEnglish (US)
Pages (from-to)3224-3229
Number of pages6
JournalSurface and Coatings Technology
Volume200
Issue number10 SPEC. ISS.
DOIs
StatePublished - Feb 24 2006

Keywords

  • AFM
  • FTIR
  • GaN
  • Reflectance
  • Sapphire
  • TEM

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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