Surface imaging of atomic force microscopy based on molecular dynamics

Abstract: Based on the non-contact atomic force microscopy (nc-AFM) imaging principle, molecular dynamics method is used for modeling non-rigid silicon tip-surface atomic-cluster interaction. With the model, in ultra low temperature environment, the imaging process of AFM tip on monocrystalline reconstructed silicon (111)-(7×7) surface is investigated. Two kinds of potential function is adopted to describe the tip-surface interaction. The atomic resolution imaging of monocrystalline silicon (111)-(7×7) surface is obtained by using two kinds of termination tips with various crystal planes. The simulation results show that distinct substructure(two crescents) images of individual Adatom on silicon (111)-(7×7) surface are obtained in some subatomic simulated images, which validates the experimental results. Furthermore, the distance between tip and surface in stable imaging conditions is discussed with certain potential and tip termination. It is shown that the deformations of tip and surface are slight during scanning process, the influence of which on the imaging effect can be neglected.