Effective geometric size and bond-loss effect in nanoelasticity of GaN nanowires

RJ Wang and CY Wang and YT Feng, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 130, 267-273 (2017).

DOI: 10.1016/j.ijmecsci.2017.06.026

This paper aims to identify a well-defined effective diameter of Nanowires (NWs) in evaluating their Young's modulus and to investigate the physical mechanisms behind the achieved surface elasticity. To this end, GaN NWs were considered for which a layer-wise model was developed and the tensile tests were performed based on molecular statics simulations (MSS). It was shown that two previously defined effective diameters result in opposing effects of the surface elasticity and reversed size -dependence of the overall Young's modulus. Subsequently, a proper effective diameter was decided for the NWs, which enables one to correctly interpret atomistic simulations in terms of continuum mechanics concepts. In particular, clear evidence was attained showing that the bond loss on the NW surface results in around 43% surface softening relative to the NW interior and bulk material. (C) 2017 Elsevier Ltd. All rights reserved.

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