Understanding the tensile behaviors of ultra-thin ZnO nanowires via molecular dynamics simulations

Weidong Wang,Fan Lei,Zhaoliang Pi,Yang Lu

doi:10.1063/1.4944499

Weidong Wang, Fan Lei + Show 2 more

Open Access

https://doi.org/10.1063/1.4944499

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Journal: AIP Advances	Publication Date: Mar 1, 2016
Citations: 12	License type: CC BY 4.0

Affiliation: University of Hong Kong, Xidian University

Abstract

By using molecular dynamics (MD) method, the tensile behavior of ultra-thin ZnO nanowires in &lt;0001 &gt; orientation with three different diameters have been investigated respectively. Through the numerical simulations, the tensile properties including Young’s modulus and yielding stress are obtained as functions of strain rates, temperatures and diameter sizes. The simulation results indicate that the nanowire Young’s modulus and yielding stress would decrease with the increasing of diameter size. In addition, a significant dependence of tensile properties on temperature was also observed with the Young’s modulus and yielding stress decreasing on average by 8% and 18% respectively, while the temperature rises from 0.1 K to 400 K. However, in our simulations the Young’s modulus and yielding stress have no obvious change with different strain rates. Lastly, the structure of ultra-thin ZnO nanowires could be transformed at the strain of ∼7%-11% while the nanowires eventually fracture at the strain of nearly 15%.

Highlights

Being a unique nanomaterial, zinc oxide (ZnO) exhibits semiconducting, piezoelectric and pyroelectric multiple properties,[1] of which the nanostructures have a variety of morphologies, such as nanowire, nanocage, nanobelt, nanocube, nanohelix/nanospring, nanoring or nanoplate
In our simulations the Young’s modulus and yielding stress have no obvious change with different strain rates
The major experiment methods, including atomic force microscopy (AFM) testing, in situ scanning electron microscopy (SEM) testing and in situ transmission electron microscopy (TEM) testing are widely utilized in the test of mechanical properties of ZnO nanowires

Summary

INTRODUCTION

Zinc oxide (ZnO) exhibits semiconducting, piezoelectric and pyroelectric multiple properties,[1] of which the nanostructures have a variety of morphologies, such as nanowire, nanocage, nanobelt, nanocube, nanohelix/nanospring, nanoring or nanoplate. Dai et al.[10] performed MD simulations of ZnO nanowires under tensile loading and compared it with the simulations of TiO2 wires to present size-dependent mechanical properties and super ductility of metal oxide wires. They found large surface-to-volume ratio is responsible for their size effects. Our work has been carried out based on MD simulations and WZ-structured ZnO nanowires in orientation of different diameter sizes are utilized to investigate the dependence of tensile properties including Young’s modulus and yielding stress on the temperature and strain-rate, which is rarely involved and important in the nanotechnology research

Physical modeling

MD simulation

Stretching process

Results and discussions

CONCLUSIONS

Conflicts of Interest