Comparison of Different Excitation Schemes in Bimodal Atomic Force Microscopy in Air and Liquid Environments

Bimodal amplitude modulation atomic force microscopy(AM-AFM)is widely used in nanoscale topography and compositional contrast imaging for various materials.In this work,we use computational simulation to compare the dynamic behaviors of AFM cantilevers in three commonly used excitation schemes in bimodal AM-AFM,i.e.,the cantilever base excitation,the cantilever end excitation,and the uniform excitation along the length of the cantilever,in both air and liquid environments.The amplitude and phase spectroscopy curves and the frequency responses acquired from the three excitation schemes are compared and discussed.The results would be useful in guiding the selection of excitation methods and the optimization of imaging conditions.