Observation of vertical honeycomb structure in InAlNGaN heterostructures due to lateral phase separation

Lin Zhou, David Smith, Martha McCartney, D. S. Katzer, D. F. Storm

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The microstructure of Inx Al1-x NGaN heterostructures (where x∼0.13-0.19), grown by molecular beam epitaxy, was investigated by transmission electron microscopy. Observations in the cross-section and plan-view geometries show evidence for lateral phase separation originating at the GaN surface that results in a vertical honeycomblike structure within the InAlN layers. The lateral dimensions of the honeycomb cells are ∼5-10 nm. The vertical walls are In rich with a width of ∼1-2 nm and align roughly perpendicular to 〈11 2- 0〉 and 〈1 1- 00〉 directions. The phase separation is attributed to random compositional fluctuations during the early stages of growth, possibly associated with misfit-strain relaxation.

Original languageEnglish (US)
Article number081917
JournalApplied Physics Letters
Issue number8
Publication statusPublished - 2007


ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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