On the elastic modulus, and ultimate strength of Ge, Ge-Si nanowires

SKD Nath and NK Peyada and SG Kim, COMPUTATIONAL MATERIALS SCIENCE, 185, 109931 (2020).

DOI: 10.1016/j.commatsci.2020.109931

Although Ngo et al. (2006) determined the Young's modulus and ultimate strength of Ge nanowires experimentally by using atomic force microscopy, orientation dependent these properties, its loading tip velocity dependent mechanical properties were not determined due to limitations of the experimental procedures. They did not visualize and explain the reasons behind their brittle fracture. Another limitation in their experimental study was that they were not able to carry out the experiment considering the diameters of nanowires below 20 nm. In the present study we model the nanowires following the experimental procedure in the range of diameter 1-30 nm using molecular dynamic simulation. Firstly, we verify the present theoretical results comparing with those of experimental studies to prove the validity of the present study. Then we calculate the orientation and indenter velocity dependent these properties. We visualize the phase change of its loading region during bending to understand their brittle fracture. The comparative study of the mechanical properties of Ge-core/Si-shell and Si-core/Ge- shell nanowires as a function of temperature are studied. Effects of temperatures and indenter velocity on the mechanical properties of Ge-Si nanowires are also studied.

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