Classification of stacking faults and dislocations observed in nonpolar a-plane GaN epilayers using transmission electron microscopy

Bo Hyun Kong, Qian Sun, Jung Han, In Hwan Lee, Hyung Koun Cho

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

In this study, we presented comparative discrimination methods to identify various line and planar defects observed in nonpolar a-GaN epilayers on r-sapphire substrates. Unlike the case of conventional c-GaN, which is dominated by perfect threading dislocations, systematic identification of undistinguishable defects using transmission electron microscopy (TEM) is necessary to suppress the propagation of defects in nonpolar GaN epilayers. Cross-sectional TEM images near the [0 0 0 1] zone axis revealed that perfect mixed and pure screw type dislocations are visible, while pure edgeand basal stacking faults (BSFs) are not discernible. In tilted cross-sectional TEM images along the 12̄10 zone axis, the dominant defects were BSFs and partial dislocations for the g=1̄010 and 0 0 0 2 two-beam images, respectively. From plan-view TEM images taken along the 112̄0 axis, it was found that the dominant partial and perfect dislocations were Frank-Shockley and mixed dislocations, respectively. Prismatic stacking faults were observed as inclined line contrast near the [0 0 0 1] zone axis and were visible as band contrast in the two-beam images along the 12̄10 and 112̄0 zone axes.

Original languageEnglish
Pages (from-to)2522-2528
Number of pages7
JournalApplied Surface Science
Volume258
Issue number7
DOIs
Publication statusPublished - 2012 Jan 15

Keywords

  • Defects
  • Metalorganic chemical vapor deposition
  • Nitrides
  • Semiconducting III-V materials

ASJC Scopus subject areas

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

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