Digital model for X-ray diffraction with application to composition and strain determination in strained InAs/GaSb superlattices

Yifei Meng, Honggyu Kim, Jean Luc Rouviére, Dieter Isheim, David N. Seidman, Jian Min Zuo

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We propose a digital model for high quality superlattices by including fluctuations in the superlattice periods. The composition and strain profiles are assumed to be coherent and persist throughout the superlattice. Using this model, we have significantly improved the fit with experimental X-ray diffraction data recorded from the nominal InAs/GaSb superlattice. The lattice spacing of individual layers inside the superlattice and the extent of interfacial intermixing are refined by including both (002) and (004) and their satellite peaks in the fitting. For the InAs/GaSb strained layer superlattice, results show: (i) the GaSb-on-InAs interface is chemically sharper than the InAs-on-GaSb interface, (ii) the GaSb layers experience compressive strain with In incorporation, (iii) there are interfacial strain associated with InSb-like bonds in GaSb and GaAs-like bonds in InAs, (iv) Sb substitutes a significant amount of In inside InAs layer near the InAs-on-GaSb interface. For support, we show that the composition profiles determined by X-ray diffraction are in good agreement with those obtained from atom probe tomography measurement. Comparison with the kinetic growth model shows a good agreement in terms of the composition profiles of anions, while the kinetic model underestimates the intermixing of cations.

Original languageEnglish (US)
Article number013513
JournalJournal of Applied Physics
Volume116
Issue number1
DOIs
StatePublished - Jul 7 2014

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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