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Title: In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

Abstract

Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPsmore » at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase - field modeling tools that can be used for future materials research at Sandia. Acknowledgeme nts This work was supported by the Laboratory Directed Research and Development (LDRD) program of Sandia National Laboratories. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidia ry of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.« less

Authors:
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1159665
Report Number(s):
SAND2014-18468
540214
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Lu, Ping. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.. United States: N. p., 2014. Web. doi:10.2172/1159665.
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Lu, Ping. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.. United States. doi:10.2172/1159665.
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Lu, Ping. Wed . "In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.". United States. doi:10.2172/1159665. https://www.osti.gov/servlets/purl/1159665.
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@article{osti_1159665,
title = {In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.},
author = {Lu, Ping},
abstractNote = {Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase - field modeling tools that can be used for future materials research at Sandia. Acknowledgeme nts This work was supported by the Laboratory Directed Research and Development (LDRD) program of Sandia National Laboratories. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidia ry of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.},
doi = {10.2172/1159665},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 01 00:00:00 EDT 2014},
month = {Wed Oct 01 00:00:00 EDT 2014}
}
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DOI:  10.2172/1159665
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  • ; ; ; ... - International Journal of Materials Research / Zeitschrift fur Metallkunde
    Aberration correction in the scanning transmission electron microscope allows spatial resolutions of the order of one ngstr m to be routinely achieved. When combined with electron energy loss spectroscopy, it is possible to simultaneously map the structure, the chemistry and even the electronic properties of materials in one single experiment. Here we will apply these techniques to the characterization of thin films and interfaces based on complex oxides with the perovskite structure. The relatively large lattice parameter of these materials combined with the fact that most of them have absorption edges within the reach of the spectrometer optics makes thesemore » materials ideal for these experiments. We will show how it is possible to map the chemistry of interfaces atomic plane by atomic plane, including light element imaging such as O. Applications to cobaltite and titanate thin films will be described.« less

  • ; ; ; ... - Physical Review Letters
    We demonstrate that a transmission electron microscope fitted with two spherical-aberration correctors can be operated as an energy-filtered scanning confocal electron microscope. A method for establishing this mode is described and initial results showing 3D chemical mapping with nanoscale sensitivity to height and thickness changes in a carbon film are presented. Importantly, uncorrected chromatic aberration does not limit the depth resolution of this technique and moreover performs an energy-filtering role, which is explained in terms of a combined depth and energy-loss response function.

  • ;
    The development of aberration correctors and their routine applications in transmission and scanning transmission electron microscopy mode have enabled sub- ngstr m imaging of practical nanoscale materials and nanocatalysts. To correctly interpret the observed image contrast of practical samples is, however, still challenging. For example, the contrast of the various features in a high-angle annular dark-field (HA-ADF) image can be affected by many parameters such as sample tilt [1], presence of amorphous materials [2], overlapping crystallites, electron-beam channeling, etc. The visibility and image contrast of individual monomers, dimers or small clusters supported on relatively thick crystalline substrates may be modulatedmore » by tilting the substrate crystal away from electron-beam channeling conditions or the major zone axes.« less

  • ; ; ; ... - Applied Physics Letters
    In this work, the atomic structure of anti-phase boundary defects at the SrTiO{sub 3}/Si (001) interface is investigated by aberration-corrected scanning transmission electron microscopy. Atomic-resolution images reveal an abrupt SrTiO{sub 3}/Si interface with no intermediate oxide layer. Both single and double Si atomic columns (“dumbbells”) from different terraces of the Si(001) surface are visible at the interface. Anti-phase boundaries (APB) consisting of two adjacent TiO{sub 2} planes in the SrTiO{sub 3} (STO) film resulting either from Si surface steps or from the merging of crystalline domains from different surface nucleation sites are identified. These APBs occur on either {110} ormore » {010} planes and both types have displacement vectors of a{sub STO}/2〈110〉.« less

  • - Physical Review Letters
    No abstract prepared.