On elastic relaxation and long wavelength microstructures in spinodally decomposed InxGa1−x.AsyP1−y epitaxial layers

M. M.J. Treacy, J. M. Gibson, A. Howie

Research output: Contribution to journalArticlepeer-review

158 Scopus citations

Abstract

The origin of the long-wavelength (100–300 nm) quasi-periodic microstructure observed in transmission electron microscopy studies of spinodally decomposed In Ga1−xAsyP1−y alloys has been investigated. The contrast is well explained by diffraction effects arising from lattice plane bending near the surfaces of the thinned specimens, such as would be induced by elastic relaxation of shear stresses accompanying a quasi-periodic lattice modulation. Excellent qualitative agreement between calculated and experimental contrasts lends weight to the claim that these contrasts, observed over part of the composition range of liquid phase epitaxy grown InxGa1−xAsyP1−y alloys, are associated with spinodal decomposition. The accompanying strain modulation amplitude is of the order of 10−3. It is suggested that speckle contrast on a smaller scale (5–15 nm) in this material may also be related to composition variations. More generally, the nature of near-surface elastic relaxation in compositionally modulated thin foils is discussed. It is emphasized that resultant distortions must be allowed for when structure-property relationships of modulated structures are to be determined from thinned samples by techniques such as transmission electron microscopy.

Original languageEnglish (US)
Pages (from-to)389-417
Number of pages29
JournalPhilosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties
Volume51
Issue number3
DOIs
StatePublished - Mar 1985
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Condensed Matter Physics
  • Physics and Astronomy (miscellaneous)
  • Metals and Alloys

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