Resolving the Nanostructure of Self Organized Thin Films using Corrected Scanning Transmission Electron Microscopy.

MRS Advances ◽  
2016 ◽  
Vol 1 (24) ◽  
pp. 1749-1754
Author(s):  
Robert D. Boyd ◽  
Viktor Elofsson ◽  
Kostas Sarakinos
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Plasma Deposition ◽  
Three Dimensional ◽  
Material Structure ◽  
Scanning Transmission Electron ◽  
Self Organized ◽  
Transmission Electron ◽  
Scanning Transmission

ABSTRACTCorrected scanning transmission electron microscopy (STEM) was used to characterise a novel thin film displaying a complex three dimensional nanostructure. The film was prepared by plasma deposition in such a way that it self-organises into layers of silver islands (each with typical dimensions of a few nanometres) within an aluminium nitride matrix. Successful application of STEM imaging and subsequent analysis was able to determine critical information about the material structure, namely island size, shape and crystalline orientation and the detection of island – matrix intermixing. Such information is essential in being able to predict the properties of this material and the approach adopted here is applicable to any similarly structured material.

Studies of Compositional Variations in Germanium Quantum Dots Grown on Silicon

2000 ◽  
Vol 638 ◽  
Author(s):  
Alan D.F. Dunbar ◽  
Matthew P. Halsall ◽  
Uschi Bangert ◽  
Alan Harvey ◽  
Philip Dawson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
The Self ◽  
Asymmetric Distribution ◽  
Scanning Transmission Electron ◽  
Self Organized ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Uk

AbstractWe report optical and scanning transmission electron microscopy studies of germanium dots grown on silicon. In an attempt to control the self-organized growth process and promote dot size uniformity the dot layers were grown on a 4.5nm Si0.6Ge0.4 alloy template layer. Photoluminescence results indicate the formation of carrier confining Ge rich islands, whilst Raman scattering results indicate the presence of an alloy throughout the structures formed. The samples were studied in the UK high resolution scanning transmission electron microscopy facility at Liverpool, UK. Energy dispersive analysis of individual line scans through the sample show that the structures are composed of an alloy throughout with an asymmetric distribution of Germanium in the dots and in the wetting layer close to the dots. We discuss the results in the light of the proposed growth mode for these dots and conclude that attempts to manipulate the composition of these dots during growth may be problematic due to the self-organized nature of their formation.

scholarly journals Quantifying Three-dimensional Chromatin Organization Utilizing Scanning Transmission Electron Microscopy: ChromSTEM

2019 ◽  
Author(s):  
Yue Li ◽  
Eric Roth ◽  
Vasundhara Agrawal ◽  
Adam Eshein ◽  
Jane Fredrick ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chromatin Structure ◽  
Scanning Transmission Electron Microscopy ◽  
Volume Concentration ◽  
Three Dimensional ◽  
Chromatin Organization ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractChromatin organization over a wide range of length scales plays a critical role in the regulation of gene expression and deciphering these processes requires high-resolution, three-dimensional, quantitative imaging of chromatin structure in vitro. Herein we introduce ChromSTEM, a method which utilizes high angle annular dark field imaging and tomography in scanning transmission electron microscopy in combination with DNA-specific staining for electron microscopy. We utilized ChromSTEM to quantify chromatin structure in cultured cells and tissue biopsies through local DNA distribution and the scaling behavior of chromatin polymer. We observed that chromatin is densely packed with an average volume concentration of over 30% with heterochromatin having a two-fold higher density compared to euchromatin. Chromatin was arranged into spatially well-defined nanoscale packing domains with fractal internal structure and genomic size between 100 and 400 kb, comparable to that of topologically associated domains. The packing domains varied in DNA concentration and fractal dimension and had one of the distinct states of chromatin packing with differential ratio of DNA content to the chromatin volume concentration. Finally, we observed a significant intercellular heterogeneity of chromatin organization even within a genetically uniform cell population, which demonstrates the imperative for high-throughput characterization of chromatin structure at the single cell level.

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