Hamaker constant and tip radius determination in dynamic atomic force microscopy
M.P. James (TU Delft - Mechanical Engineering)
F. Alijani – Mentor (TU Delft - Dynamics of Micro and Nano Systems)
G.J. Verbiest – Mentor (TU Delft - Dynamics of Micro and Nano Systems)
U. Staufer – Graduation committee member (TU Delft - Micro and Nano Engineering)
P. Belardinelli – Coach (TU Delft - Dynamics of Micro and Nano Systems)
A. Chandrashekar – Coach
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Abstract
Dynamic Atomic Force Microscopy (dAFM) is an extremely powerful tool for exploring surface topology and nanoscale manipulation and characterization. A feature of dAFM is the existence of highly nonlinear forces between a cantilever tip and sample. One of these forces that plays a large role in operation of AFM is the van der Waals (vdW) force. This force is characterized in part by the Hamaker constant H and cantilever tip radius R. Measuring these two properties quickly and accurately can facilitate further characterization methods in dAFM. This research will focus on creating methods in which H and R can be extracted using the dynamic response of a cantilever. The vdW force was used to extract H by analyzing the softening behavior of Frequency Response Curves (FRCs). Electrostatic forces were used to extract R by applying a simplified Kelvin Probe Force Microscopy (KPFM) technique. The method to extract H was demonstrated numerically, and the method to extract R was proven experimentally and validated using a Scanning Electron Microscopy (SEM) image.