March 2009

Journal

Column-by-column compositional mapping by Z-contrast imaging

By:
Molina Rubio, Sergio I; Varela Del Arco, Maria ; Sales Lerida, David ; Galindo, Pedro; Fuster, David; Gonzalez, Yolanda; Alen, B.; Gonzalez, Luisa; Pennycook, Stephen J
Journal Name:
Ultramicroscopy
Page Number:
172-176
Volume:
109
Issue Number:
2
Publication Date:
March 2009
View DOI Listing:
https://doi.org/10.1016/j.ultramic.2008.10.008

Abstract

A phenomenological method is developed to determine the composition of materials, with atomic column resolution, by analysis of integrated intensities of aberration-corrected Z-contrast scanning transmission electron microscopy images. The method is exemplified for InAsxP1-x alloys using epitaxial thin films with calibrated compositions as standards. Using this approach we have determined the composition of the two-dimensional wetting layer formed between self-assembled InAs quantum wires on InP (001) substrates. The method utilizes a series of B coefficients that models the background signal in Z-contrast images, which is unaccounted for by image simulations.