Quantitative extraction of in-plane surface properties using torsional resonance mode of atomic force microscopy

In the torsional resonance mode of atomic force microscopy (AFM), torsional amplitude and phase shift have been used for in-plane surface property imaging. However, no quantitative relation between torsional amplitude/phase shift and surface properties has yet been established. This paper studies how lateral contact stiffness and viscosity affect the torsional vibration of the cantilever in AFM. A basic methodology to extract in-plane surface properties is described and its effectiveness is demonstrated by quantitatively extracting the lateral contact stiffnesses and viscosities of two different materials: Si(100) and epoxy.