Frequency Response of AFM Nano Robot in Liquid by Considering the Effect of Cantilever Dimension and Environmental Parameters

Dynamic analysis and study of atomic force microscopy in liquid environment are the main goal of this research. Hydrodynamic and squeeze film forces act on the cantilever of atomic force microscopy which operate in liquid environment. The present paper investigates the effect of different environmental and physical factors on frequency response diagrams. The frequency response analysis studies the occurrence possibility of a phenomenon which causes disturbance and decreases accuracy of imaging. Timoshenko beam model and finite element method were used to be simulated. Meanwhile, the interaction forces between sample and tip point in gas and liquid environments were also considered in simulations. Achieved results showed that in comparison with gas, resonance frequency decreases considerably in liquid environment which is due to additional mass of liquid and also amplitude decreases in liquid environment for additional damping due to presence of liquid. Meanwhile, several studies in repulsion and attraction area with more and less distance from equilibrium distance, showed that in repulsion state, stimulation frequency is more than attraction area; the reason is related to more hardness in repulsion area, and also the presence of interaction forces revealed the fact that the amplitude is not zero in zero excitation frequency.