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

• Published in: Physical chemistry chemical physics : PCCP 2018, Vol.2 (13), p.8647-8657
• Main Authors: Pial, Turash Haque, Rakib, Tawfiqur, Mojumder, Satyajit, Motalab, Mohammad, Akanda, M. A. Salam
• Format: Article
• Language: English
• Subjects: Cleavage; Crystal structure; Deformation; Dynamic structural analysis; Fracture mechanics; High temperature; Indium phosphides; Mechanical properties; Molecular dynamics; Nanowires; Planes; Strain rate; Temperature; Tensile stress; Wurtzite; Zincblende
• ISSN: 1463-9076; 1463-9084
• 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. Molecular dynamics tensile simulations reveal that the cleavage fracture plane of ZB InP NWs varies with temperature, while the cleavage plane of WZ InP NWs remains fixed at all temperatures.