Quantitative electrostatic force measurement in AFM

2000-04-02
JEFFERY, Steve
Oral, Ahmet
Pethica, John B.
We describe a method for measuring forces in the atomic force microscope (AFM), in which a small amplitude oscillation(similar to 1 Angstrom(p-p)) is applied to a stiff(similar to 40 N/m) cantilever below its first resonant frequency, and the force gradient is measured directly as a function of separation. We have used this instrument to measure electrostatic forces by applying an ac voltage between the tip and the sample, and observed a variation in contact potential difference with separation. We also show how the benefits of this instrument may be exploited to make meaningful capacitance measurements, especially at small tip-surface separations, and demonstrate the potential of this technique for quantitative dopant profiling in semiconductors.
Applied Surface Science

Suggestions

Free surface wave interaction with an oscillating cylinder
Bozkaya, Canan (2014-01-01)
The numerical solution of the special integral form of two-dimensional continuity and unsteady Navier Stokes equations is used to investigate vortex states of a horizontal cylinder undergoing forced oscillations in free surface water wave. This study aims to examine the consequence of degree of submergence of the cylinder beneath free surface at Froude number 0.4. Calculations are carried out for a single set of oscillation parameters at a Reynolds number of R = 200. Two new locked-on states of vortex forma...
Properties of light and heavy baryons in light cone qcd sum rules formalism
Azizi, Kazem; Özpineci, Altuğ; Department of Physics (2009)
In this thesis, we investigate the masses, form factors and magnetic dipole moments of some light octet, decuplet and heavy baryons containing a single heavy quark in the framework of the light cone QCD sum rules. The magnetic dipole moments can be measured considering radiative transitions within a multiplet or between multiplets. Analyzing the transitions among the baryons and calculating the above mentioned parameters can give us insight into the structure of those baryons. In analyzing the aforementione...
Assessment and improvement of elementary force computations for cold forward rod extrusion
Ocal, M; Egemen, N; Tekkaya, AE (2005-06-01)
Two commonly used analytical force computation methods for cold forward rod extrusion are evaluated by means of precise finite element computations. The upperbound model by Avitzur based on the spherical velocity field and the model by Siebel based on a quasi-upper-bound solution are considered. It has been found that the pure deformation forces obtained by summing the ideal force and shear force terms deviate between +25% and -20% from the finite element solutions. Larger deviations, however, occur for the...
Quantitative atom-resolved force gradient imaging using noncontact atomic force microscopy
Oral, Ahmet; ÖZER, HAKAN ÖZGÜR; HOFFMANN, PM; PETHICA, JB (2001-09-17)
Quantitative force gradient images are obtained using a sub-angstrom amplitude, off-resonance lever oscillation method during scanning tunneling microscopy imaging. We report the direct observation of short-range bonds, and the measured short-range force interaction agrees well in magnitude and length scale with theoretical predictions for single bonds. Atomic resolution is shown to be associated with the presence of a prominent short-range contribution to the total force interaction. It is shown that the b...
Numerical Simulation of Reciprocating Flow Forced Convection in Two-Dimensional Channels
Sert, Cüneyt (ASME International, 2003-5-20)
<jats:p>Numerical simulations of laminar, forced convection heat transfer for reciprocating, two-dimensional channel flows are performed as a function of the penetration length, Womersley (α) and Prandtl (Pr) numbers. The numerical algorithm is based on a spectral element formulation, which enables high-order spatial resolution with exponential decay of discretization errors, and second-order time-accuracy. Uniform heat flux and constant temperature boundary conditions are imposed on certain regions of the ...
Citation Formats
S. JEFFERY, A. Oral, and J. B. Pethica, “Quantitative electrostatic force measurement in AFM,” Applied Surface Science, pp. 280–284, 2000, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/43089.