Molecular dynamics simulations of friction behaviours on nano-textured silicon surfaces

Molecular dynamics simulations have been applied to study the friction behaviours of nano-textured silicon surfaces. The effects of texture shape, texture pitch and indenter size on forces, temperature, stress and plastic deformation are investigated. It is found that the presence of the texture facilitates the reduction of friction due to the decrease the contact area. The texture shape significantly influences the tribological properties of the textured surface. The hemispherical texture has the optimum friction reduction effect, followed by cylindrical texture and lastly by cubic texture. The number of atoms that undergo phase transformation in the scratching is the maximal for the cubic texture while the smallest for the hemispherical texture. However, the texture pitch has little effect on the tribological properties of the textured surface. In addition, it is interesting to observe the indenter size effect that a larger indenter causes a smaller force and wear volume at the initial stage of scratching. The indenter size effect on tribological properties results from the variation of contact area in the scratching. The insights gained can shed light on the friction mechanism of nanoscale textured silicon surface and are beneficial to the design of micro/nanoscale devices such as micro/nanoelectromechanical systems with surface textures.