Nanoidentation of silicon surfaces: Molecular-dynamics simulations of atomic force microscopy

We investigate the atomic-scale details of atomic force microscopy through a quasistatic molecular dynamics simulation together with a density-functional-based tight-binding method. The changes in the AFM tip shape, the size of the tip-sample contact area, as well as the microscopic hardness and Young’s moduli of silicon {111},{110},{100} surfaces are studied. Furthermore, the effects of hydrogen termination of the surface and of subsurface vacancies on hardness and Young’s modulus are discussed.