Structural characterization of III-nitrides using electron microscopy

David Smith, Lin Zhou, Martha McCartney

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Electron microscopy methods have been used in recent collaborative studies to investigate the defect microstructure of III-nitride materials and devices. An approach based on convergent beam diffraction allowed the elemental composition of pseudomorphic InGaN/GaN quantum well structures to be determined on the nanometer scale. Indium compositional fluctuations in InGaN quantum wells caused local electric field inhomogeneities that seemed to be more pronounced near the onset of InGaN layer growth, suggesting strain relaxation as a strong contributing factor.. Relaxed InN quantum dots were invariably associated with threading dislocations in the underlying GaN buffer layer, and the interfacial misfit was accommodated by periodic dislocation arrays. Lateral phase separation in InAlN/GaN heterostructures possibly originating from misfit-strain relaxation at the heterointerface, resulted in the development of a vertical 'honeycomb' structure. The structural and electronic properties of AlGaN/GaN heterostructures grown by molecular beam epitaxy have been correlated with the Al/N flux ratio during nucleation layer growth. Electron microscopy played a central role in contributing to the development of ferromagnetic Cr-doped nitride semiconductors.

Original languageEnglish (US)
Title of host publicationGallium Nitride Materials and Devices II
StatePublished - 2007
EventGallium Nitride Materials and Devices II - San Jose, CA, United States
Duration: Jan 22 2007Jan 25 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherGallium Nitride Materials and Devices II
Country/TerritoryUnited States
CitySan Jose, CA


  • Convergent beam electron diffraction
  • Electron holography
  • III-nitride
  • Lateral phase separation
  • Multiple quantum well
  • Polarization field
  • Quantum dot
  • Spintronics
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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