Mechanical Properties of a Silicon Nanofilm Covered With Perfect or Defected Graphene

Y. Jing
Harbin Institute of Technology, CN

Keywords: Si nanofilm, graphene, mechanical properties, defects, molecular dynamics

Summary:

Molecular dynamics simulations are used to investigate the mechanical properties of a silicon nanofilm covered with perfect or defected graphene. Our results show that graphene can not only enhance the mechanical properties of a silicon nanofilm but also unify the mechanical properties of the silicon nanofilms among different crystal orientations. The Young’s modulus and critical stress of the silicon nanofilm along four classic crystal orientations covered with graphene decrease as the thickness of the silicon nanofilm increases. In addition, we study the effects of monatomic vacancies and Stone-Wales (SW) defects with various concentrations on the mechanical properties of a silicon nanofilm covered with defected graphene. The results show that Young’s modulus is reduced with a linear dependence for monatomic vacancies and a relatively smaller dependence on SW defects, while the critical stress is more sensitive to the presence of these two defects. The results in this paper demonstrate that it has very practical significance to use graphene to enhance the mechanical properties of the silicon nanofilm.