Application of HAADF STEM image analysis to structure determination in rotationally disordered and amorphous multilayered films

Mitchson, Gavin; Ditto, Jeffrey; Woods, Keenan N.; Westover, Richard D.; Page, Catherine J.; Johnson, David C.

doi:10.1088/0268-1242/31/8/084003

Cited by 6 publications

(16 citation statements)

References 54 publications

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“…High angle annular dark field (HAADF) -scanning transmission electron microscopy (STEM) [1] is widely used for the investigation of the morphology and composition of materials at atomic scale [2][3][4][5]. The analysis of single dopant atom in crystalline structures [6], defects within structures [7], interfacial discontinuity [8][9][10] or structural strain [11] are some of the advantageous outcomes of this method.…”

Section: Introductionmentioning

confidence: 99%

Modified qHAADF method for atomic column-by-column compositional quantification of semiconductor heterostructures

et al. 2018

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The qHAADF method allows the quantification of the composition at atomic column resolution in semiconductor materials by comparing the HAADF-STEM intensities between a region of interest to a region of the material of known composition. However, the application of this qHAADF approach requires both regions to be differentiable and included in the same micrograph at close proximity. This limits the application of this approach to certain materials and magnifications where this requirement is fulfilled. In this work, we extend the qHAADF method to analyses where the reference region is imaged in a separate micrograph. The validity of this modified method is proved by comparison to the original qHAADF approach using HAADF-STEM simulated images of the semiconductor heterostructure InSb/InAs. Additionally, the methods are applied successfully to experimental images both of a simple InSb/InAs interface and of a complex InSb/GaSb heterostructure, justifying the significance of the modified method over the original method.

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Section: Introductionmentioning

confidence: 99%

Modified qHAADF method for atomic column-by-column compositional quantification of semiconductor heterostructures

et al. 2018

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“…A variety of approaches have been used to gain insight into the structure of amorphous films, including X-ray reflectivity (XRR), − ellipsometry, grazing incidence X-ray diffraction (GIXRD), transmission electron microscopy (TEM), electron diffraction, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), , extended X-ray absorption fine structure spectroscopy (EXAFs), , and solid-state nuclear magnetic resonance (ss-NMR). , Although these traditional techniques provide a variety of structural details, there remains a distinct deficiency in accurately determining the local and mid-range atomic structure of nanostructured materials. X-ray total scattering measurements and pair distribution function (PDF) analysis have yielded significant structural information about bulk amorphous and nanostructured materials, specifically in determining local to long-range order. − However, there has been much less reported use of PDF analysis to examine thin films on a substrate, due to complicated data analysis procedures and assumptions required about the sample volume and geometry. , Additionally, in the case of amorphous metal oxides, the low scattering power of O further complicates X-ray structural studies.…”

Section: Introductionmentioning

confidence: 99%

“…A variety of approaches have been used to gain insight into the structure of amorphous films, including X-ray reflectivity (XRR), 17−19 ellipsometry, 20 grazing incidence X-ray diffraction (GIXRD), 21 transmission electron microscopy (TEM), 22 electron diffraction, 23 high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), 24,25 extended X-ray absorption fine structure spectroscopy (EXAFs), 26,27 and solid-state nuclear magnetic resonance (ss-NMR). 28,29 Although these traditional techniques provide a variety of structural details, there remains a distinct deficiency in accurately determining the local and mid-range atomic structure of nanostructured materials.…”

Section: ■ Introductionmentioning

confidence: 99%

Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis

et al. 2017

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Amorphous metal oxides are central to a variety of technological applications. In particular, indium gallium oxide has garnered attention as a thin-film transistor channel layer material. In this work we examine the structural evolution of indium gallium oxide gel-derived powders and thin films using infrared vibrational spectroscopy, X-ray diffraction, and pair distribution function (PDF) analysis of X-ray total scattering from standard and normal incidence thin-film geometries (tfPDF). We find that the gel-derived powders and films from the same aqueous precursor evolve differently with temperature, forming mixtures of Ga-substituted InO and In-substituted β-GaO with different degrees of substitution. X-ray total scattering and PDF analysis indicate that the majority phase for both the powders and films is an amorphous/nanocrystalline β-GaO phase, with a minor constituent of InO with significantly larger coherence lengths. This amorphous β-GaO phase could not be identified using the conventional Bragg diffraction techniques traditionally used to study crystalline metal oxide thin films. The combination of Bragg diffraction and tfPDF provides a much more complete description of film composition and structure, which can be used to detail the effect of processing conditions and structure-property relationships. This study also demonstrates how structural features of amorphous materials, traditionally difficult to characterize by standard diffraction, can be elucidated using tfPDF.

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“…Rietveld refinements of the specular XRD patterns of the [(LaSe) 1.17 ] 1 V n (1+ y )+1 Se 2 n +2 heterostructures with n = 2 and 3 were based on the positions of atomic planes along the c -axis extracted from the vertical intensity profiles in the HAADF-STEM images of the n = 3 compound. We used Gaussian peak fitting to determine peak locations with subpixel accuracy and averaged the results from different images to obtain initial estimates for the z -coordinate of each atomic plane in the heterostructures . The STEM produced initial model has two plane positions for the atomic layers of Se and the fully occupied V layer and one for the nominally half occupied V layer.…”

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confidence: 99%

Expanding the Concept of van der Waals Heterostructures to Interwoven 3D Structures

et al. 2017

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Several members of a new family of heterostructures [(LaSe)1.17]1V n(1+y)+1Se2n+2 with n = 1, 2, and 3 were prepared using a diffusion constrained, kinetically controlled synthesis approach. Specular diffraction patterns collected as a function of annealing temperature show the evolution of designed precursors into highly ordered heterostructures. Scanning transmission electron microscopy (STEM) images reveal that the structure of n = 3 consists of rock salt structured LaSe bilayers alternating with vanadium selenide layers of varying thickness, which are structurally closely related to V3Se4. Interplanar distances obtained from the STEM images were successfully used as the starting point for Rietveld refinements of the specular diffraction patterns of these crystallographically aligned compounds. Utilizing this unorthodox combined approach to extract detailed structural information unambiguously, we demonstrated that these thin film compounds are the first examples of chalcogenide-based heterostructures, where the bulk structures of both building blocks lack a van der Waals gap, yet a nonepitaxial incommensurate interface forms. Moreover, the refinement results of the n = 2 and 3 heterostructures suggest that the structure of the V–Se layers can be varied ranging from VSe2 to VSe depending on the film composition. The electrical resistivity of the [(LaSe)1.17]1V n(1+y)+1Se2n+2 heterostructures changes systematically from semiconducting toward metallic behavior with increasing n, showcasing the ability to tune physical properties by precisely controlling the layer sequence in these heterostructures.

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Application of HAADF STEM image analysis to structure determination in rotationally disordered and amorphous multilayered films

Cited by 6 publications

References 54 publications

Modified qHAADF method for atomic column-by-column compositional quantification of semiconductor heterostructures

Modified qHAADF method for atomic column-by-column compositional quantification of semiconductor heterostructures

Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis

Expanding the Concept of van der Waals Heterostructures to Interwoven 3D Structures

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