Peak separation method for sub-lattice strain analysis at atomic resolution: Application to InAs/GaSb superlattice

Honggyu Kim; Yifei Meng; Jean-Luc Rouviére; Jian-Min Zuo

doi:10.1016/j.micron.2016.10.003

Peak separation method for sub-lattice strain analysis at atomic resolution: Application to InAs/GaSb superlattice

Micron. 2017 Jan:92:6-12. doi: 10.1016/j.micron.2016.10.003. Epub 2016 Oct 21.

Authors

Honggyu Kim¹, Yifei Meng¹, Jean-Luc Rouviére², Jian-Min Zuo³

Affiliations

¹ Dept of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA; Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA.
² CEA/INAC/SP2M/LEMMA, 19 rue des Martyrs, 38 054 Grenoble, France.
³ Dept of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA; Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA. Electronic address: jianzuo@illinois.edu.

PMID: 27816744
DOI: 10.1016/j.micron.2016.10.003

Abstract

We report on a direct measurement of cation and anion sub-lattice strain in an InAs/GaSb type-II strained layer superlattice (T2SLs) using atomic resolution imaging and advanced image processing. Atomic column positions in InAs and GaSb are determined by separating the cation and anion peak intensities. Analysis of the InAs/GaSb T2SLs reveals the compressive strain in the nominal GaSb layer and tensile strain at interfaces between constituent layers, which indicate In incorporation into the nominal GaSb layer and the formation of GaAs like interfaces, respectively. The results are compared with the model-dependent X-ray diffraction measurements in terms of interfacial chemical intermixing and strain. Together, these techniques provide a robust measurement of atomic-scale strain which is vital to determine T2SL properties.