20 January 2012 Quantitative strain analysis of interfaces in InAs/GaSb superlattices by aberration-corrected HAADF-STEM
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The strain distribution across interfaces in InAs/GaSb superlattices is investigated by scanning transmission electron microscopy (STEM), using an aberration corrected probe. Atomic resolution images of the superlattices (grown on (100)-GaSb substrates) were acquired using the high-angle annular dark field (HAADF) imaging technique. For quantitative strain analysis, the peak-pair algorithm was used to determine the local atomic displacements across interfaces and within individual layers in the structure. The measured displacements were then used to calculate the strain map with respect to a reference lattice in the GaSb-substrate region. To precisely identify the local regions in the strain map Fourier transformation of the HAADF-STEM image was performed to obtain the chemically-sensitive (200)- Fourier component of the image. A comparison of these images with strain profiles determined from the strain maps revealed that the GaSb-on-InAs interface is GaAs-like, with a tensile strain of - 0.018 ± 0.003, whereas the overall strain at the InAs-on-GaSb interface was negligible. In addition, the strain within the GaSb layers was found to be compressive, with a magnitude of 0.008 ± 0.003, indicating In incorporation in these layers.
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K. Mahalingam, K. Mahalingam, H. J. Haugan, H. J. Haugan, G. J. Brown, G. J. Brown, K. G. Eyink, K. G. Eyink, Bin Jiang, Bin Jiang, } "Quantitative strain analysis of interfaces in InAs/GaSb superlattices by aberration-corrected HAADF-STEM", Proc. SPIE 8268, Quantum Sensing and Nanophotonic Devices IX, 826831 (20 January 2012); doi: 10.1117/12.911914; https://doi.org/10.1117/12.911914

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