Atomistic investigation on the mechanical properties and failure behavior of zinc-blende cadmium selenide (CdSe) nanowire

Abstract

Understanding the mechanical properties of cadmium selenium (CdSe) nanowire has received intense research interest due to its versatile application in semiconductor industries. We investigated the tensile mechanical properties and fracture mechanism of zinc-blende CdSe nanowire (NW) through molecular dynamics simulations by considering the effects of temperature variation, NW size, different loading directions, vacancy defects, and strain rates. We found that both ultimate tensile strength (UTS) and Young’s modulus (YM) linearly decrease with increasing temperature but increase with nanowire cross-sectional area. The [111] -directed CdSe NW shows the largest UTS, YM, and fracture toughness whereas, the lowest values are obtained for [100] direction. The largest failure strain is exhibited by [110] direction. The UTS is found more sensitive in the presence of Cd vacancy, while the YM is more sensitive to the removal of Se atoms. We noticed that at 100 K, the [100] -directed CdSe NW fails along {111} cleavage plane, however, at 600 K, both {111} and {100} cleavage planes activate and cause fracture at a lower strain value. Finally, both the fracture strength and strain increase with the increment in strain rates. The mechanical properties and fracture characteristics of the CdSe NW elucidated in this study will be a guide to design and fabricate CdSe-based optoelectronic and electronic devices.