Misfit dislocation generation in InGaN epilayers on free-standing GaN

Rong Liu, Jin Mei, Sridhar Srinivasan, Hiromasa Omiya, Fernando Ponce, David Cherns, Yukio Narukawa, Takashi Mukai

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

We have found that, in the absence of threading dislocations in In xGa1-xN/GaN heterostructures, coherent generation of misfit dislocations occurs for x > 0.11 in ∼100-nm-thick epilayers. We focus this report on In0.17Ga0.83N grown on a low-defect-density GaN free-standing substrate (with 1.9% lattice mismatch). A diffraction contrast analysis carried out in the transmission electron microscope showed straight line defects with Burgers vectors 2/3 〈112̄0〉 (i.e., 2a, where a is the hexagonal plane lattice parameter), which extended many micrometers approximately along 〈11̄00〉 directions and with an average lateral spacing of 90nm. Although these defects were complex and mostly sessile, evidence was found that they can dissociate into glissile misfit dislocations with Burgers vectors of 1/3 〈112̄0〉. It is proposed that the defects are generated by a punch-out mechanism involving slip on inclined prismatic planes. The properties of these defects and their role in relieving misfit strains are discussed.

Original languageEnglish (US)
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume45
Issue number20-23
DOIs
StatePublished - Jun 2 2006

Fingerprint

Epilayers
Dislocations (crystals)
Burgers vector
Defects
defects
Lattice mismatch
Defect density
relieving
punches
Lattice constants
Heterojunctions
Electron microscopes
Diffraction
micrometers
lattice parameters
slip
electron microscopes
spacing
Substrates
diffraction

Keywords

  • Epitaxy on bulk GaN
  • InGaN epilayers
  • Misfit dislocations
  • Plastic relaxation
  • Punch-out relaxation process

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Misfit dislocation generation in InGaN epilayers on free-standing GaN. / Liu, Rong; Mei, Jin; Srinivasan, Sridhar; Omiya, Hiromasa; Ponce, Fernando; Cherns, David; Narukawa, Yukio; Mukai, Takashi.

In: Japanese Journal of Applied Physics, Part 2: Letters, Vol. 45, No. 20-23, 02.06.2006.

Research output: Contribution to journalArticle

Liu, Rong ; Mei, Jin ; Srinivasan, Sridhar ; Omiya, Hiromasa ; Ponce, Fernando ; Cherns, David ; Narukawa, Yukio ; Mukai, Takashi. / Misfit dislocation generation in InGaN epilayers on free-standing GaN. In: Japanese Journal of Applied Physics, Part 2: Letters. 2006 ; Vol. 45, No. 20-23.
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