A simplified but intuitive analytical model for intermittent-contact-mode force microscopy based on Hertzian mechanics

[摘要] The forces acting on the substrate in intermittent-contact-mode (IC mode, tapping mode) atomic force microscopy are not accessible to a direct measurement. For an estimation of these forces, a simple analytical model is developed by considering only the shift of the cantilever resonance frequency caused by Hertzian (contact) forces. Based on the relationship between frequency shift and tip-sample force for large-amplitude frequency-modulation atomic force microscopy, amplitude and phase versus distance curves are calculated for the intermittent contact mode, and the forces on the substrate are calculated. The results show a qualitative agreement with numerical calculations, yielding typical maximal forces of 50-150 nN. When working above the unperturbed resonance, forces are found to be significantly larger than below the resonance. (C) 1999 Elsevier Science B.V. All rights reserved.

[发布日期] 1999-10-10

[关键词] atomic force microscopy;intermittent contact;tapping mode