Calibration of rectangular atomic force microscope cantilevers

TLDR

The Sader et al. method for cantilever calibration required knowledge of both density and thickness, whereas the present approach does not. This study proposes a method to determine the spring constant of a rectangular AFM cantilever using only its resonant frequency, quality factor, and plan‑view dimensions. The method relies on measuring the resonant frequency and quality factor of the cantilever in fluid and applying the known plan‑view dimensions. The method delivers very good accuracy and outperforms the previous Sader et al.

Abstract

A method to determine the spring constant of a rectangular atomic force microscope cantilever is proposed that relies solely on the measurement of the resonant frequency and quality factor of the cantilever in fluid (typically air), and knowledge of its plan view dimensions. This method gives very good accuracy and improves upon the previous formulation by Sader et al. [Rev. Sci. Instrum. 66, 3789 (1995)] which, unlike the present method, requires knowledge of both the cantilever density and thickness.