A molecular dynamics simulation study of irradiation induced defects in gold nanowire
WQ Liu and PH Chen and RZ Qiu and M Khan and J Liu and MD Hou and JL Duan, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 405, 22-30 (2017).
Displacement cascade in gold nanowires was studied using molecular dynamics computer simulations. Primary knock-on atoms (PKAs) with different kinetic energies were initiated either at the surface or at the center of the nanowires. We found three kinds of defects that were induced by the cascade, including point defects, stacking faults and crater at the surface. The starting points of PICAS influence the number of residual point defects, and this consequently affect the boundary of anti-radiation window which was proposed by calculation of diffusion of point defects to the free surface of nanowires. Formation of stacking faults that expanded the whole cross-section of gold nanowires was observed when the PICA's kinetic energy was higher than 5 keV. Increasing the PICA's kinetic energy up to more than 10 keV may lead to the formation of crater at the surface of nanowires due to microexplosion of hot atoms. At this energy, PICAS started from the center of nanowires can also result in the creation of crater because length of cascade region is comparable to diameter of nanowires. Both the two factors, namely initial positions of PICAS as well as the craters induced by higher energy irradiation, would influence the ability of radiation resistance of metal nanowires. (C) 2017 Elsevier B.V. All rights reserved.
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