Molecular dynamics study on ZnO nanowires mechanical properties: Strain rate, temperature and size dependent effects

Abstract

Using molecular dynamics simulations, strain rate, temperature, size and orientation dependent mechanical properties of zinc oxide (ZnO) nanowire are carried out with tensile loading. It is found that, for the same cross-sectional areas, strain rates have almost no effect on Young's modulus, provided strain rates are within the range from 0.001 to 0.03 ps-1. Our calculated results have also demonstrated that, as temperature ranging from 200 K to 1600 K, ZnO nanowires' Young's modulus are all monotonically decreasing with increasing temperature. Furthermore, at the temperature of 300 K, yield strength, Young's modulus, fracture strength and fracture strain increase dramatically with increasing cross sectional area. It is also demonstrated that, with increasing cross sectional area, the Young's modulus of ZnO nanowires eventually approaching that of bulk single-crystal ZnO. Finally, orientation dependent ZnO mechanical properties of nanowires have been studied at 300 K.