Atomistic investigations on the mechanical properties and fracture mechanisms of indium phosphide nanowires

TH Pial and T Rakib and S Mojumder and M Motalab and MAS Akanda, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 20, 8647-8657 (2018).

DOI: 10.1039/c7cp08252e

The mechanical properties of indium phosphide (InP) nanowires are an emerging issue due to the promising applications of these nanowires in nanoelectromechanical and microelectromechanical devices. In this study, molecular dynamics simulations of zincblende (ZB) and wurtzite (WZ) crystal structured InP nanowires (NWs) are presented under uniaxial tension at varying sizes and temperatures. It is observed that the tensile strengths of both types of NWs show inverse relationships with temperature, but are independent of the size of the nanowires. Moreover, applied load causes brittle fracture by nucleating cleavage on ZB and WZ NWs. When the tensile load is applied along the 001 direction, the direction of the cleavage planes of ZB NWs changes with temperature. It is found that the 111 planes are the cleavage planes at lower temperatures; on the other hand, the 110 cleavage planes are activated at elevated temperatures. In the case of WZ NWs, fracture of the material is observed to occur by cleaving along the (0001) plane irrespective of temperature when the tensile load is applied along the 0001 direction. Furthermore, the WZ NWs of InP show considerably higher strength than their ZB counterparts. Finally, the impact of strain rate on the failure behavior of InP NWs is also studied, and higher fracture strengths and strains at higher strain rates are found. With increasing strain rate, the number of cleavages also increases in the NWs. This paper also provides in-depth understanding of the failure behavior of InP NWs, which will aid the design of efficient InP NWs- based devices.

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