Time-resolved compositional mapping during in situ TEM studies

Persson, Axel R.; Tornberg, Marcus; Sjökvist, Robin; Jacobsson, Daniel

doi:10.1016/j.ultramic.2020.113193

Cited by 5 publications

(3 citation statements)

References 33 publications

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“…From the correlation, we extracted the individual correction factors (CFs) from the derivative (i.e., linear fit) of the pressure readings defined according toIn this case, we determine the uniform correction factor over the pressure range for N 2 as 1.2, based on the data as presented in black in Figure 4. Using the experimental data presented for AsH 3 (gray) and PH 3 (magenta) we determined the gas correction factors for pressures between 0.001 and 10 Pa, which is the attainable pressure range within the microscope during for crystal growth (Maliakkal et al, 2019; Tornberg et al, 2020; Persson et al, 2021). As a result of the MPG400 being a dual pressure gauge, we extracted correction factors for both the cold-cathode filament (<0.06 Pa) and the Pirani element (1–10 Pa).…”

Section: Resultsmentioning

confidence: 99%

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

Tornberg

Maliakkal

Jacobsson

et al. 2022

Microscopy and Microanalysis

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The world of environmental microscopy provides the possibility to study and analyze transformations and reactions during realistic conditions to understand the processes better. We report on the design and development of a metal-organic chemical vapor deposition (MOCVD) system integrated with an environmental transmission electron microscope intended for real-time investigations of crystal growth. We demonstrate methods for achieving a wide range of precisely controlled concentrations of precursor gas at the sample, as well as for calibrating the sample partial pressure using the pressure measured elsewhere in the microscope column. The influences of elevated temperature and reactive gas within the pole-piece gap are evaluated with respect to imaging and spectroscopy. We show that X-ray energy-dispersive spectroscopy can be strongly affected by temperatures beyond 500 $^{\circ }$ C, while the spatial resolution is largely unaffected by heat and microscope pressure for the relevant conditions. Finally, the influence of the electron beam on the investigated processes is discussed. With this work, we aim to provide crucial input in the development of advanced in situ electron microscopy systems for studies of complex reactions in real time under realistic conditions, for instance as used during formation of semiconductor crystals.

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Section: Resultsmentioning

confidence: 99%

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

Tornberg

Maliakkal

Jacobsson

et al. 2022

Microscopy and Microanalysis

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“…Environmental or in situ TEM measurements have enabled depicting growth dynamics of semiconductor nanowires growing both under vapor–liquid–solid (VLS) [ 88 ] and vapor-solid-solid (VSS) growth regimens by tracking the seed and the NW composition during growth. In particular, for the case of Au-seeded GaAs NWs, despite showing comparable growth rates, incubation, and atomic layer completion, they follow opposite trends for the two growth modes (i.e., short incubation and long completion for VLS; long incubation and short completion for VSS) [ 89 ].…”

Section: In Situ Stemmentioning

confidence: 99%

STEM Tools for Semiconductor Characterization: Beyond High-Resolution Imaging

Mata

Molina

2022

Nanomaterials

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The smart engineering of novel semiconductor devices relies on the development of optimized functional materials suitable for the design of improved systems with advanced capabilities aside from better efficiencies. Thereby, the characterization of those materials at the highest level attainable is crucial for leading a proper understanding of their working principle. Due to the striking effect of atomic features on the behavior of semiconductor quantum- and nanostructures, scanning transmission electron microscopy (STEM) tools have been broadly employed for their characterization. Indeed, STEM provides a manifold characterization tool achieving insights on, not only the atomic structure and chemical composition of the analyzed materials, but also probing internal electric fields, plasmonic oscillations, light emission, band gap determination, electric field measurements, and many other properties. The emergence of new detectors and novel instrumental designs allowing the simultaneous collection of several signals render the perfect playground for the development of highly customized experiments specifically designed for the required analyses. This paper presents some of the most useful STEM techniques and several strategies and methodologies applied to address the specific analysis on semiconductors. STEM imaging, spectroscopies, 4D-STEM (in particular DPC), and in situ STEM are summarized, showing their potential use for the characterization of semiconductor nanostructured materials through recent reported studies.

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“…The As and Au signals were carefully monitored for the nanoparticle and the nanowire, respectively, to make sure that the beam was condensed at a point sufficiently far from the interface as to not record signal from the other region. Arsenic has very low solubility in the Au droplet, 20 and very little Au is incorporated into the nanowire; 21 therefore, these signals clearly show whether the beam should be condensed further from the interface. A few measurements were discarded due to the As in the nanoparticle or the Au in the nanowire being measured as higher than 5 atomic percent, which was set as the cutoff limit.…”

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confidence: 99%

Compositional Correlation between the Nanoparticle and the Growing Au-Assisted In_xGa_1–xAs Nanowire

Sjökvist

Jacobsson

Tornberg

et al. 2021

J. Phys. Chem. Lett.

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The nanowire geometry is favorable for the growth of ternary semiconductor materials, because the composition and properties can be tuned freely without substrate lattice matching. To achieve precise control of the composition in ternary semiconductor nanowires, a deeper understanding of the growth is required. One unknown aspect of seeded nanowire growth is how the composition of the catalyst nanoparticle affects the resulting composition of the growing nanowire. We report the first in situ measurements of the nanoparticle and In x Ga 1– x As nanowire compositional relationship using an environmental transmission electron microscopy setup. The compositions were measured and correlated during growth, via X-ray energy dispersive spectroscopy. Contrary to predictions from thermodynamic models, the experimental results do not show a miscibility gap. Therefore, we construct a kinetic model that better predicts the compositional trends by suppressing the miscibility gap. The findings imply that compositional control of In x Ga 1– x As nanowires is possible across the entire compositional range.

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Time-resolved compositional mapping during in situ TEM studies

Cited by 5 publications

References 33 publications

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

STEM Tools for Semiconductor Characterization: Beyond High-Resolution Imaging

Compositional Correlation between the Nanoparticle and the Growing Au-Assisted In_xGa_1–xAs Nanowire

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Time-resolved compositional mapping during in situ TEM studies

Cited by 5 publications

References 33 publications

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

Enabling In Situ Studies of Metal-Organic Chemical Vapor Deposition in a Transmission Electron Microscope

STEM Tools for Semiconductor Characterization: Beyond High-Resolution Imaging

Compositional Correlation between the Nanoparticle and the Growing Au-Assisted InxGa1–xAs Nanowire

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Product

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Compositional Correlation between the Nanoparticle and the Growing Au-Assisted In_xGa_1–xAs Nanowire