Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

• Miriam Jaafar,
• David Martínez-Martín,
• Mariano Cuenca,
• John Melcher,
• Arvind Raman and
• Julio Gómez-Herrero

Beilstein J. Nanotechnol. 2012, 3, 336–344, doi:10.3762/bjnano.3.38

• high quality factor Q of the cantilevers in vacuum, which present a settling time given by τcl= Q/(πf0). Frequency-modulation AFM (FM-AFM, also known as noncontact AFM) [9] is the classical alternative to AM allowing atomic resolution in UHV chambers [10] at higher scanning rates. FM-AFM has recently

• difficult to apply low forces in AM, which are necessary to obtain stable virus images [27], for example. Since the demonstration of true atomic resolution in liquids by Fukuma et al. [11] using FM [28], this mode has attracted the attention of the AFM community in attempts to image biological samples with

• studies, e.g., atomically flat single crystals. Using DAM in liquids we have already been able to obtain true atomic resolution on a mica surface (see Supporting Information File 1) but atomic resolution in vacuum remains a challenge. DAM can also improve magnetic force imaging since it allows operating

Models of the interaction of metal tips with insulating surfaces

• Thomas Trevethan,
• Matthew Watkins and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2012, 3, 329–335, doi:10.3762/bjnano.3.37

• atomic resolution. Chromium and tungsten tips are used to image the NaCl(001) and MgO(001) surfaces. The interaction of the tips with the surface is simulated by using density-functional-theory calculations employing a mixed Gaussian and plane-wave basis and cluster-tip models. In each case, the apex of

• . Keywords: atomic force microscopy; density functional theory; ionic surfaces; metallic asperities; surface interactions; Introduction The noncontact atomic force microscope (NC-AFM) is capable of imaging both conducting and insulating systems with true atomic resolution and has provided extraordinary

• fact, in many cases atomic-resolution images are only obtained after the tip has been deliberately crashed into the surface, implying that the tip apex is formed from surface species [1][2]. The development of NC-AFM based on a quartz tuning fork (qPlus sensor) instead of a silicon cantilever has led

Dipole-driven self-organization of zwitterionic molecules on alkali halide surfaces

• Laurent Nony,
• Franck Bocquet,
• Franck Para,
• Frédéric Chérioux,
• Eric Duverger,
• Frank Palmino,
• Vincent Luzet and
• Christian Loppacher

Beilstein J. Nanotechnol. 2012, 3, 285–293, doi:10.3762/bjnano.3.32

• create atomic-scale defects (see for example the upper part of Figure 3b). For a detailed investigation of the lattice parameters of both the molecular protrusions in the MSPS islands and the Moiré pattern respectively, we proceeded as follows: first, atomic-resolution images of the substrate surface

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

• the important oscillation stability [8][9][10]. The key factor to achieve atomic resolution is the proper choice of several parameters, for example, the spring constant and the oscillation amplitude (see Table I in [11]). Theoretically, the optimal signal-to-noise ratio (SNR) is achieved at a value of

• , and reliable interpretation of the atomic contrast becomes very difficult. The next milestone in AFM history was the introduction of the frequency-modulation (FM)-AFM technique by Albrecht and co-workers [4]. By applying this method Giessibl demonstrated the possibility of achieving true atomic

• resolution on the prototypical Si(111) 7×7 surface [5]. Among others, this seminal work initiated a fast progression of the FM-AFM technique over the past decade [6][7]. At the beginning, mainly silicon-based cantilevers oscillating with large amplitudes (tens of nanometers) were used, because they possess

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

• -AFM) has brought considerable advancement to the atomic-scale study of surfaces, by allowing both atomic-resolution imaging and atomically resolved force spectroscopy. Generally, these advancements have been made on atomically flat crystalline surfaces. Yet, many surfaces of technological interest are

• for exfoliated graphene, which may be probed with UHV scanning tunneling microscopy (yielding full atomic resolution, as demonstrated by several groups) [3][4][5][6][7]. The controversy arises when STM measurements of graphene/SiO2 are compared with AFM measurements of the bare SiO2 substrate, because

• ], and its anomalous frictional behavior [16]. Beyond graphene, the use of SiO2 is commonplace as a substrate in electronic-device research (carbon-nanotube devices, organic electronics, etc.). While one may readily obtain atomic resolution on certain flat surfaces, such as the well-studied (7 × 7

A measurement of the hysteresis loop in force-spectroscopy curves using a tuning-fork atomic force microscope

• Manfred Lange,
• Dennis van Vörden and
• Rolf Möller

Beilstein J. Nanotechnol. 2012, 3, 207–212, doi:10.3762/bjnano.3.23

• ) [1] has made it possible to achieve true atomic resolution [2] with a NC-AFM. In this mode the distance between the sample and the tip is adjusted by maintaining the frequency shift of the cantilever at a constant value while scanning the sample. During operation the oscillation amplitude is kept

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

• and in particular a direct atomic-scale characterization of the surface structure is largely missing for a range of important metal oxides. In recent years, the noncontact atomic force microscope (NC-AFM) has been established as a unique tool to provide atomic-resolution real-space images of all types

qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution

• Maximilian Schneiderbauer,
• Daniel Wastl and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2012, 3, 174–178, doi:10.3762/bjnano.3.18

• combined STM/AFM measurements with atomic resolution [10]. However, in standard MFM experiments, this large k, in combination with the resonance frequency f0 ≈ 31000 Hz, leads to very small frequency shifts (Equation 1). Whereas MFM experiments employing quartz tuning forks, with both prongs oscillating

Noncontact atomic force microscopy

• Udo D. Schwarz

Beilstein J. Nanotechnol. 2012, 3, 172–173, doi:10.3762/bjnano.3.17

• conference from this series was held in Lindau, Germany, from September 18–22, 2011. Once again, substantial progress was presented; NC-AFM is now able to quantitatively map three-dimensional force fields of surfaces with atomic resolution in ultrahigh vacuum as well as in liquids, and methodological

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

• Adam Sweetman,
• Sam Jarvis,
• Rosanna Danza and
• Philip Moriarty

Beilstein J. Nanotechnol. 2012, 3, 25–32, doi:10.3762/bjnano.3.3

• Adam Sweetman Sam Jarvis Rosanna Danza Philip Moriarty School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, U.K. 10.3762/bjnano.3.3 Abstract Background: Noncontact atomic force microscopy (NC-AFM) now regularly produces atomic-resolution images on a wide range of

• ; noncontact AFM; qPlus; Si(001); Si(100); tip (apex) structure; Introduction It is now generally accepted that atomic resolution in NC-AFM imaging on semiconducting surfaces is due to the chemical force between the atoms of the surface and the last few atoms of the tip apex [1][2][3][4]. Even with well

• tips were prepared by standard STM methods (voltage pulses, controlled contacts with the sample) until good atomic resolution was obtained in STM feedback, at which point we made the transition to NC-AFM (i.e., Δf) feedback. As a result of our tip preparation procedures our tips are likely to be

Current-induced dynamics in carbon atomic contacts

• Jing-Tao Lü,
• Tue Gunst,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2011, 2, 814–823, doi:10.3762/bjnano.2.90

• right, carbon nanotube- or graphene-based nanostructures may offer an interesting test bed for studies of current-induced effects at the atomic scale. For such systems, experiments with atomic resolution, employing for instance state-of-the-art electron microscopes, can be performed in the presence of

Oriented growth of porphyrin-based molecular wires on ionic crystals analysed by nc-AFM

• Thilo Glatzel,
• Lars Zimmerli,
• Shigeki Kawai,
• Ernst Meyer,
• Leslie-Anne Fendt and
• Francois Diederich

Beilstein J. Nanotechnol. 2011, 2, 34–39, doi:10.3762/bjnano.2.4

• distinct advantages compared to other surfaces. Flat surfaces with monoatomic steps and large terraces are easily prepared and electron bombardment leads to well-structured surfaces [34]. Additionally, these materials have rather large unit cells which allow to obtain atomic resolution fairly easily [35

• only very stable, inexpensive and quickly accessible, but also both the periphery and the central metal are very easy to modify. Therefore, such porphyrin wires can be tuned with a high degree of freedom. FFT-analysis of measurements [26] showing simultaneous molecular and atomic resolution of the

•  3b and Figure 3c show a 30 × 30 nm2 topography image of the assembly, already revealing submolecular details as well as atomic resolution of the underlying KBr. First, the molecular assembly is not aligned along a certain substrate direction of the KBr layer. The rows are inclined by ≈10° to the [010

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

• surface termination by NC-AFM with atomic resolution, point defects in magnesium oxide on Ag(001) and line defects in aluminum oxide on NiAl(110), respectively, were thoroughly studied. The contact potential was determined by Kelvin probe force microscopy (KPFM) and the electronic structure by scanning

• tunneling spectroscopy (STS). On magnesium oxide, different color centers, i.e., F0, F+, F2+ and divacancies, have different effects on the contact potential. These differences enabled classification and unambiguous differentiation by KPFM. True atomic resolution shows the topography at line defects in

• makes atomic resolution on conductors [7] as well as on insulators [8] possible. In addition to investigations on the surface topography, site specific spectroscopy measurements can be performed [8]. The whole setup is placed in a sound absorber cabin and is carried on a wooden frame, which, in turn, is

Scanning probe microscopy and related methods

• Ernst Meyer

Beilstein J. Nanotechnol. 2010, 1, 155–157, doi:10.3762/bjnano.1.18

• were drastically improved. Atomic resolution on metals, semiconductors [3] and insulators was achieved. Recently, the atomic structure of single molecules was identified by nc-AFM, which gives new opportunities to investigate the local structure of these molecules [4]. In this Thematic Series, the

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• . While HRTEM and electron diffraction does not provide absolute quantification of the ordering parameter as can be achieved by scanning (S)TEM at atomic resolution at its mass sensitive contrast [74], it allows a relatively fast way to distinguish between ordered and disordered phases. For the purpose of