Simultaneous current, force and dissipation measurements on the Si(111) 7×7 surface with an optimized qPlus AFM/STM technique

• Zsolt Majzik,
• Martin Setvín,
• Andreas Bettac,
• Albrecht Feltz,
• Vladimír Cháb and
• Pavel Jelínek

Beilstein J. Nanotechnol. 2012, 3, 249–259, doi:10.3762/bjnano.3.28

• STM/AFM measurements on the Si(111) 7×7 surface using our modified sensor. The measurements were performed in the constant frequency shift mode at room temperature. To compensate for long-range electrostatic forces, the bias voltage was adjusted to the minimum of the Kelvin parabola (generally about

Modeling noncontact atomic force microscopy resolution on corrugated surfaces

• Kristen M. Burson,
• Mahito Yamamoto and
• William G. Cullen

Beilstein J. Nanotechnol. 2012, 3, 230–237, doi:10.3762/bjnano.3.26

• is minimized, especially when seeking accurate topography of corrugated surfaces. The model used does not account for local bonding, electrostatic forces, or atomistic interactions beyond the inclusion of a pairwise vdW interaction, all of which affect the AFM resolution; nonetheless, even if these

• rough surfaces, the model itself oversimplifies the multifaceted complexities of experimental AFM setups. More complex models, which include short-range bonding and electrostatic forces, more realistic tip geometries, and calculations for closer proximities between tip and sample, are needed for a more

An NC-AFM and KPFM study of the adsorption of a triphenylene derivative on KBr(001)

• Antoine Hinaut,
• Adeline Pujol,
• Florian Chaumeton,
• David Martrou,
• André Gourdon and
• Sébastien Gauthier

Beilstein J. Nanotechnol. 2012, 3, 221–229, doi:10.3762/bjnano.3.25

• still very scarce [6][8]. Coupling these two techniques is not only interesting for the characterization of the electrical properties of the adsorbates, but also for the extraction of topographic images that are free from distortion induced by electrostatic forces [27]. In the following, we present the

• normalized frequency shifts [33] γ = kA3/2Δf/f0 = 0.25 fN·m1/2 at most (k ~ 40 N·m−1). Under these conditions the interaction of the tip with the surface is quite small and it is expected that only van der Waals and electrostatic forces contribute to the image. Note that at the Kelvin voltage, provided that

Noncontact atomic force microscopy study of the spinel MgAl₂O₄(111) surface

• Morten K. Rasmussen,
• Kristoffer Meinander,
• Flemming Besenbacher and
• Jeppe V. Lauritsen

Beilstein J. Nanotechnol. 2012, 3, 192–197, doi:10.3762/bjnano.3.21

• scanning the surface. The surface potential, measured after annealing the crystal, was generally quite high, often in the range 4–8 V. Therefore, the voltage applied between the surface and the tip, Ubias, was monitored and adjusted regularly to minimize the electrostatic forces arising from the contact

Molecular-resolution imaging of pentacene on KCl(001)

• Julia L. Neff,
• Jan Götzen,
• Enhui Li,
• Michael Marz and
• Regina Hoffmann-Vogel

Beilstein J. Nanotechnol. 2012, 3, 186–191, doi:10.3762/bjnano.3.20

• -range electrostatic forces, the tip–sample work-function difference was compensated by application of the appropriate bias voltage to the tip. Results and Discussion Figure 1a shows the KCl(001) surface with submonolayer coverage of pentacene molecules forming an extended island over several microns

Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group

• Einat Tirosh,
• Enrico Benassi,
• Silvio Pipolo,
• Marcel Mayor,
• Michal Valášek,
• Veronica Frydman,
• Stefano Corni and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2011, 2, 834–844, doi:10.3762/bjnano.2.93

• the electrostatic forces. The Nose–Hoover thermostat [28] was used (time constant for coupling of 0.1 ps). The time step for the simulations was 2 fs (bond lengths were constrained with the LINCS algorithm) [29]. The long-range electrostatic contribution was computed with the PME method with a direct

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• microscopy (KPFM) and MFM. The KPFM technique allows us to compensate in real time the electrostatic forces between the tip and the sample by minimizing the electrostatic contribution to the frequency shift signal. This is a great challenge in samples with low magnetic moment. In this work we studied an

• by other long range interactions, i.e., the electrostatic forces. These kinds of images can be erroneously interpreted as magnetic contrast in the case of complex magnetic materials. In order to determine the origin of this contrast we varied the electric field between the tip and the sample. Instead

• ] was used in combination with MFM to adjust the tip bias voltage to minimize electrostatic forces between the tip and the sample at every point on the sample (Figure 4b). In both of the scans (main scan and retrace mode), the normal force, amplitude, phase, frequency shift and surface potential (in the

The role of the cantilever in Kelvin probe force microscopy measurements

• George Elias,
• Thilo Glatzel,
• Ernst Meyer,
• Alex Schwarzman,
• Amir Boag and
• Yossi Rosenwaks

Beilstein J. Nanotechnol. 2011, 2, 252–260, doi:10.3762/bjnano.2.29

• distance profile which stems from the cantilever first resonance shape, while the second is a result of the change in the cantilever shape in its second resonance mode; this leads to a differentially weighted effect of the electrostatic forces along the cantilever. These two effects were analyzed and are

• minimized by applying an additional DC bias to give the CPD. In the previous sections this was modeled by nullifying the entire electrostatic force acting on the probe. However, this analysis is not accurate since the electrostatic forces at different points along the cantilever have a different effect on

• point along the cantilever by using A = δz' in Equation 3. In this situation, the entire virtual work Wz(r) done by the external electrostatic forces in the z direction, for a probe positioned at r, is given by where and are the local forces acting at point r' on the cantilever and the tip

Single-pass Kelvin force microscopy and dC/dZ measurements in the intermittent contact: applications to polymer materials

• Sergei Magonov and
• John Alexander

Beilstein J. Nanotechnol. 2011, 2, 15–27, doi:10.3762/bjnano.2.2

• method of separating the mechanical and electrostatic forces helps, however, measurements of the electrostatic force at remote tip–sample distances limit their sensitivity and, particularly, spatial resolution. Therefore, it may be advantageous to check the capabilities of single-pass KFM at ambient

• contact regime. In other words, imaging at the set-point amplitude (Asp) below its transition value will insure a profiling of surface topography, and at higher Asp the imaging will proceed in the non-contact mode when the probe experiences long-range forces such as electrostatic forces. This is

• sample. Here we would like to comment on a comparison of KFM results obtained in the AM–FM and AM–AM modes. The KFM images presented in Figure 3 were obtained in AM–FM mode. The earlier KFM studies of F14H20 self-assemblies on different substrates revealed that the FM detection of the electrostatic

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• . For larger amplitudes, a more general relation can be derived [12], which is not always proportional, however, strictly monotonic. Consequently, the tip-sample forces and potentials can be determined by recording Δf with NC-AFM. Via detection of electrostatic forces, contact potentials can be

Sensing surface PEGylation with microcantilevers

• Natalija Backmann,
• Natascha Kappeler,
• Thomas Braun,
• François Huber,
• Hans-Peter Lang,
• Christoph Gerber and
• Roderick Y. H. Lim

Beilstein J. Nanotechnol. 2010, 1, 3–13, doi:10.3762/bjnano.1.2

• (electrostatic forces, structural changes and steric competition) [14]. This sensitivity to structural changes in static mode operation has shown to be particularly suited for measuring binding processes based on conformational changes of molecules attached to the microcantilever’s surface such as proteins [25