Mechanical anisotropy and tension-compression asymmetry of Au coated Si nanowafers: An atomistic approach

Combined gold and silicon nanosystem has spurred tremendous interest in the scientific community due to its application in different metal-semiconductor electronic devices and solar driven water splitting cells. Silicon, fabricated on gold layer, is prone to gold atom diffusion at its surface. In this study, detailed analysis of anisotropic mechanical properties of Au coated Si nanowafer is studied by performing molecular dynamics tensile and compressive simulations. The effect of crystallographic orientation of silicon on the mechanical properties of Au coated Si nanowafer is observed for Si crystal oriented along [100], [110] and [111] directions. The crystal orientation of silicon is varied and concurrently the tension-compression asymmetry is investigated. Reverse tension-compression asymmetry is observed in case of loading along [110] crystal orientation. The failure mechanism reveals that crystal transformation of silicon occurs during compression leading to an early yielding of the material.