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Silicon is one of the most technologically important materials, used extensively in electronics, solar cells, micro-electro-mechanical systems (MEMS) based devices and more. Yet its mechanical properties are not well understood at the nanoscale where it is often utilized. Experimental measurements under a variety of loading conditions are needed, and compression experiments are particularly lacking. Here, the elastic-plastic response of 20-65 nm cubic Si nanocubes under uniaxial compression is investigated. The purely elastic limit of these nanocubes is observed to be up to 0.07 true strain at 7 GPa true stress with an upper yield point of 0.20 true strain and 11 GPa true stress. Investigation of the nature of dislocations generated during deformation of these nanocubes using post-mortem analysis in the TEM provides evidence that leading partial dislocations are the dominant source of plasticity at this scale.
Bibliographical noteFunding Information:
This work was supported in part by NSF MRSEC under awards DMR-0819885 and DMR-1420013. STEM analysis was carried out in the Characterization Facility of the University of Minnesota, which receives partial support from the NSF through the MRSEC program. Multislice computer simulations were performed using resources provided by the Minnesota Supercomputing Institute. The authors would like to thank Doug Stauffer and Ryan Major of Hysitron for their continued support.
© 2015 Acta Materialia Inc.Published by Elsevier Ltd. All rights reserved.
- In situ transmission electron microscopy (TEM)
- Mechanical properties
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- Period 2