Analysis of Subsurface Imaging and Effect of Contact Elasticity in the Ultrasonic Force Microscope

Abstract

We examined, both theoretically and experimentally, the characteristics of subsurface imaging with nanometer resolution and the effect of contact elasticity in the ultrasonic force microscope (UFM). In particular, the effect of the surface energy and effective elasticity on the maximum tip-sample force and the shift of the averaged tip-sample distance were examined. Furthermore, kink formation in the cantilever deflection (z a) against the ultrasonic frequency vibration (UFV) amplitude (a) characteristics was predicted. This model was used to explain experimental observations in UFM, such as the features of the measured z a(a) curve and the damping of the cantilever torsion vibration by the UFV. Moreover, the previously reported lateral ultrasonic force microscope image of subsurface features was explained by the response of subsurface edge dislocation to a large instantaneous force enhanced by the UFV.

The Simultaneous Determination of the Forces and Viscoelastic Properties of Adsorbed Polymer Layers

“…They split the possible operation modes into three general sections. Modulation via the sample (27), via the tip (where the lever root is moved) (32), and force modulation, where the force is applied directly at the probe (30) (there are important distinctions between these approaches (29)). …”

“…Perpendicular excitations have been used (14 -18), lateral "friction" forces have also been studied (19 -21), and many AFM workers have attempted to extract a modulus "map" as the sample is imaged in the AFM (22)(23)(24)(25)(26). More recently various authors have attempted to determine quantitative information from their force curves (27)(28)(29)(30)(31)(32). This is the approach adopted here to obtain information on the viscoelastic properties of an adsorbed gelatin film.…”

Application of scanning probe microscopy to the characterization and fabrication of hybrid nanomaterials

“…Thus, for a given driving amplitude, the average repulsive force and resulting cantilever displacement will be greater on a stiffer surface. Thus, UFM curves contain information about the adhesive contact forces and the modulus of the surface (Inagaki et al, 2002;Szoszkiewicz et al, 2003;Yamanaka et al, 1994).…”

Visualization of buried structures in atomic force acoustic microscopy

“…Of special interest are mechanical elasticity and deformation, to be gathered with the high local resolution typical for AFM. Elastic properties of the surface and surface near areas can be imaged with Atomic Force Acoustic Microscopy (AFAM) [3] or Ultrasonic Force Microscopy (UFM) [4,5]. In AFAM, flexural and torsional cantilever vibrations are excited by out-of-plane and in-plane sample surface vibrations.…”