ABSTRACT
Frequency modulation atomic force microscopy (FM-AFM) has been
widely applied to the surface science field as a nondestructive, high-
resolution imaging method, which is based on the highly sensitive
detection of interaction forces between samples and the atomic
force microscope probe tip utilizing the sharp resonance of the
cantilever vibration (high quality factor [Q-factor]) [1, 2]. However, high-resolution imaging in liquids by FM-AFM is severely hindered
by the extreme reduction of the Q-factor due to the hydrodynamic interaction between the cantilever and the liquid. Recently, the
use of small-amplitude mode and the large noise reduction in the
cantilever deflection sensor has brought great progress in FM-AFM
imaging in liquids [3, 4], which allows us to directly investigate in
vivo molecular-scale biological processes. In this chapter, the details
of the problems in FM-AFM imaging in liquids, the frequency noise
analysis of the cantilever oscillation in low-Q environments, and the improvements of FM-AFM in liquids are described. The present
status of the high-resolution FM-AFM imaging is also presented.
Furthermore, the three-dimensional (3D) force (frequency shift:
