Simulation of imaging in tapping-mode atomic-force microscopy: a comparison amongst a variety of approaches

Models capable of accurate simulation of microcantilever dynamics coupled with complex tip-sample interactions are essential for interpretation and prediction of the imaging results in amplitude modulation or tapping-mode atomic-force microscopy (AM-AFM or TM-AFM). In this paper, four approaches based on combinations of lumped and finite element methods for modelling of cantilever dynamics, and van der Waals and molecular dynamics for modelling of tip-sample interactions, are used to simulate the precise imaging by AM-AFM. Based on the simulated imaging and force determination, the efficiency of different modelling schemes is evaluated. This comparison is performed considering their coincidence with the realistic behaviour of AM-AFM in imaging of nanoscale features. In the conducted simulations, a diamond tip is used to scan a C60 molecule absorbed on a graphite substrate. The effects of amplitude set-point, cantilever stiffness and quality factor on the accuracy of different modelling approaches are studied.