The role of topography and friction for the image contrast in lateral force microscopy

Abstract

A theoretical analysis of the lateral force as measured with a scanning force microscope is performed, showing that the lateral force signal contains a topography-induced component which is proportional to the slope of the surface, in addition to the signal arising from the tangential force. Measurements carried out on corrugated samples (gold, indium-tin-oxide, diamond) are analysed within the framework of this theory on the basis of a simple physical model for the forces, taking into account a repulsive normal force, a tangential friction force, and an adhesion force. The correlation between the lateral force and the topography is confirmed quantitatively. Furthermore, friction mfficients are determined and the influence of the adhesion force on the data is discussed.

Quantitative nanofriction characterization of corrugated surfaces by atomic force microscopy

“…Parameters such as roughness, granularity, power spectrum of the surface play an important role. The effects of surface topography on nano-friction measurements have been studied, although a general theory is still lacking [8,9,10,11,12]. In many cases, attention has been concentrated on flat crystalline surfaces under ultra-high-vacuum (UHV), where the influence of surface topography is negligible [13,14,15,16].…”

Scanning Force Microscopy Studies of Implanted Silicon Crystals

“…In angular representation the lateral force and cantilever torsion angle follow the dependence φ = 3.9 x 10 3 F Iat. The friction force may be extracted from the lateral force image and separated from topographical component by subtraction of the data sets corresponding to opposite directions of scanning (left-right and right-left) [6]. Both images are collected during single measurements.…”

“…For the loading force in the range of tenths of nΝ many papers [8,9,6,10] prove the linear dependence of the SFM lateral force value and the loading force, therefore simple friction equation FF = const + μFL is justified. The average loading force was in this measurement about 20 nΝ.…”

“…• mica: μ = 0.09 [9], • diamond film on a Si substrate: μ = 0.18 [6], • gold film on mica: μ = 0.16-0.21 [6], • PTO (indium-tin-oxide) film on glass: μ = 0.11 [6]. However, the reproducibility of our measurements is rather poor (±30%), most probably due to the surface contamination (all measurements were done in ambient air).…”

Influence of spring stiffness and anisotropy on stick-slip atomic force microscopy imaging

“…However, the three translational degrees of freedom of the scanning probe often account for an unwanted mix of frictional and topographic information. [1][2][3][4] This mixing is influenced by the type of detection that is used and is most prominent with optical lever detection. Another aspect is the influence of the scanning configuration or system itself.…”