Dimer/tetramer motifs determine amphiphilic hydrazine fibril structures on graphite

• Loji K. Thomas,
• Nadine Diek,
• Uwe Beginn and
• Michael Reichling

Beilstein J. Nanotechnol. 2012, 3, 658–666, doi:10.3762/bjnano.3.75

• –graphite interface by self-assembly of custom-designed symmetric and asymmetric amphiphilic benzamide derivatives bearing C10 aliphatic chains. Scanning tunnelling microscopy (STM) studies reveal geometry-dependent internal structures for the elementary fibrils of the two molecules that are distinctly

• ; interface; self-assembly; STM; Introduction One-dimensional micro- and nanostructures of organic compounds are important for solution-processable organic electronic devices [1][2][3], and electron transport through organic molecules is also the basis for a large number of biological processes [4

• (fibres) in bulk columnar mesophases depends mostly on X-ray techniques, which suffice for many purposes [7][10][11]. However, information in real space, as provided by scanning tunnelling microscopy (STM), offers unparalleled advantages to the synthesis chemist who strives to functionalize fibrils that

Strong spin-filtering and spin-valve effects in a molecular V–C₆₀–V contact

• Mohammad Koleini and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2012, 3, 589–596, doi:10.3762/bjnano.3.69

• Plads, Building 345E, DK-2800 Kongens Lyngby, Denmark 10.3762/bjnano.3.69 Abstract Motivated by the recent achievements in the manipulation of C60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C60 molecule in an STM tunneljunction with a magnetic tip

• mainly majority-spin electrons to pass (>95%). Moreover, we find a significant change in the conductance between parallel and anti-parallel spin polarizations in the junction (86%) which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems

• experimentally. Recently, it has been demonstrated in low temperature scanning tunneling microscopy (STM) experiments how C60 molecules can be picked up by the STM-tip, and how they could controllably be used to contact structures such as adatoms, clusters, and molecules placed on a substrate surface [5][6][7

Combining nanoscale manipulation with macroscale relocation of single quantum dots

• Francesca Paola Quacquarelli,
• Richard A. J. Woolley,
• Martin Humphry,
• Jasbiner Chauhan,
• Philip J. Moriarty and
• Ashley Cadby

Beilstein J. Nanotechnol. 2012, 3, 324–328, doi:10.3762/bjnano.3.36

• beneficial, as has been shown for STM imaging [22]. By using this method it is possible to greatly increase the number of manipulations that can be completed, and it allows for the possibility of performing manipulations to create an individual and distinctive structure in each cell without the need for an

Graphite, graphene on SiC, and graphene nanoribbons: Calculated images with a numerical FM-AFM

• Fabien Castanié,
• Laurent Nony,
• Sébastien Gauthier and
• Xavier Bouju

Beilstein J. Nanotechnol. 2012, 3, 301–311, doi:10.3762/bjnano.3.34

• (STM) or Raman spectroscopy [73][74][75][76][77][78][79]. Recently, the ability to create nanoribbons of graphene [80][81][82] arises because such a system exhibits a gap opening, thus providing a semiconducting behavior to the material. Actually, the structure of the edge of these nanoribbons of few

• ][41][42][43][44][104][105][106]. Indeed, there is a discrepancy in the interpretation of the brightest features on the surface. By coupling STM and FM-AFM [41][44], one may identify the actual graphite structure observed in the images. Nevertheless, the role played by the tip (structure and

• chemical edge modification. Before reaching this stage, precise characterization of the structure of the edges has to be tackled experimentally by transmission electronic microscopy, scanning tunneling microscopy (STM) or calculations [79][82][112][113][114][115][116][117][118]. Generally, GNRs show a

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

• determine its exact conformation in the well-ordered islands observed on KCl. Makoudi et al. [23] used scanning tunneling microscopy (STM) to measure MSPS on Au(23 23 21) and observed a parallelogram unit cell with dimensions of 1.1 × 0.5 nm2, and the molecules were adsorbed in the so-called scorpion-like

• conformation. The dipole moment of the molecule, which in this conformation is oriented perpendicular to the substrate surface, could only be imaged with low contrast, or not at all, by STM, due to its reduced conductivity and the fact that it is flexible. In order to draw conclusions about the most probable

• , similar to the STM experiments [23], the two protrusions observed in the experimental pattern must be the aromatic rings, which are separated by 6.5 Å. This distance is too large to fit the experimentally observed pattern when the molecules are aligned along the direction of the substrate (Figure 4a, I

Junction formation of Cu₃BiS₃ investigated by Kelvin probe force microscopy and surface photovoltage measurements

• Fredy Mesa,
• William Chamorro,
• William Vallejo,
• Robert Baier,
• Thomas Dittrich,
• Alexander Grimm,
• Martha C. Lux-Steiner and
• Sascha Sadewasser

Beilstein J. Nanotechnol. 2012, 3, 277–284, doi:10.3762/bjnano.3.31

• 3% aqueous NH3 solution for 150 s at room temperature and transferred through air into the UHV system within less than 5 min. Kelvin probe force microscopy Kelvin probe force microscopy measurements were performed in a modified Omicron UHV AFM/STM operating at room temperature and a base pressure

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

• interferometric deflection. Keywords: AFM; cross-talk; current; dissipation; force; qPlus; STM; tuning fork; Introduction The invention of scanning probe techniques, in particular scanning tunneling microscopy (STM) [1] and atomic force microscopy (AFM) [2], had a tremendous impact on our understanding of the

• physical, chemical and material properties of surfaces and nanostructures at the atomic scale. STM is based on the detection of the tunneling current between a probe and a sample, and it turned quickly into a standard technique widely used to characterize conductive surfaces and to modify objects at the

• atomic scale. Unfortunately, the requirement of conductive samples strongly prevents the STM technique from potential applications on nonconductive surfaces, e.g., technologically important oxide materials. This serious limitation was overcome by the introduction of AFM, which detects forces acting

Analysis of force-deconvolution methods in frequency-modulation atomic force microscopy

• Joachim Welker,
• Esther Illek and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2012, 3, 238–248, doi:10.3762/bjnano.3.27

• scanning tunneling microscope (STM), extending the imaging capabilities to insulators [1]. Nowadays the focus of development and investigation shifts from purely topographic imaging, in spite of this still being the main use of an AFM, to quantitative force measurements between single atoms or molecules in

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

• 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

• AFM measurements of SiO2 generally show a much smoother topography than is shown by STM of graphene/SiO2. Motivated by the experimental difficulty in measuring SiO2 surfaces, we propose a model to gain insight into this issue. Here we present experimental findings on SiO2 that have motivated the

• physics that describes the crumpling of soft membranes [10]. More recently, a study comparing scanning-probe measurements of the corrugation of single-layer graphene (by UHV STM) with that of SiO2 (by ambient AFM) reported a significantly greater corrugation for the graphene than that observed for the SiO2

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

• ) ultrahigh vacuum STM/AFM (Omicron NanoTechnology GmbH, Taunusstein, Germany). The original optical beam-deflection system was improved by replacing the LED by a superluminescent laser diode (Superlum, Moscow, Russia) coupled to the system by an optical fiber. The control electronics were from Nanonis (SPECS

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

• 77 K with a home-built low-temperature tuning-fork-based AFM (LT-TF-AFM) [9]. When a conductive sample is used, scanning tunneling microscopy (STM) and FM-AFM measurements may be combined. The use of a tuning fork as a sensor allows an oscillation amplitude in the subnanometer regime to be used, due

• in three different phases, namely the herringbone, square and hexagonal phases. Results and Discussion Figure 1a shows an STM 250 nm × 250 nm overview scan of the PTCDA/Ag/Si(111) √3 × √3 surface after the deposition of ~0.3 ML PTCDA. The PTCDA molecules grow from step edges or between steps and form

• 77 K under ultrahigh vacuum (UHV) conditions. Measurements were performed using a home-built LT-TF-AFM [9], which is able to operate both as an STM and as an FM-AFM. The tuning fork is used in the qPlus configuration [22]. The oscillation amplitude of the tuning fork can be chosen in the subnanometer

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

• STM/AFM microscope, X-ray photoelectron spectroscopy (XPS) and means for sample preparation. The MgAl2O4 single crystal used for this NC-AFM study was purchased from the MTI Corporation with an EPI polished (111) facet. The crystal was first rinsed in a 1:1 mixture of nitric acid (65%) and water

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

• ; pentacene; scanning force microscopy; self-assembly; Introduction To understand the functionalization of surfaces with molecular building blocks, an important step is to study the self-assembly of molecules. Scanning tunneling microscopy (STM) enables such studies on conductive surfaces [1][2]. On metallic

• organic electronic devices [13]. The adsorption of pentacene on various substrates has been investigated with diffraction methods and STM [14][15][16][17][18]. On single crystalline metal surfaces such as, e.g., Cu(110), Au(111) and Ag(111) [19][20][21][22][23][24], pentacene forms a wetting layer of flat

• , template-induced growth from one monolayer to thick films was studied by STM [18]. The molecular arrangement even on the top of islands with several nanometers in height appears to be commensurate with the graphite surface. On the more inert SiO2, templating is not possible, due to the disordered substrate

Quantitative multichannel NC-AFM data analysis of graphene growth on SiC(0001)

• Christian Held,
• Thomas Seyller and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2012, 3, 179–185, doi:10.3762/bjnano.3.19

• . Towards this goal, the graphene layer thickness has been determined by various methods including scanning tunnelling microscopy (STM) [4], Raman spectroscopy [5], low-energy electron microscopy [6][7], transmission electron microscopy [8], and atomic force microscopy (AFM) [9][10]. AFM also allows the

• identification of the graphene layer thickness from the local contact potential as determined by means of Kelvin probe force microscopy (KPFM) [11][12]. As a further advantage, KPFM determines step heights more accurately than STM or AFM with constant bias [13] and is therefore employed in this study to

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

• in real space, variations of Scanning Tunneling Microscopy (STM) [1] and Atomic Force Microscopy (AFM) [2] are used. To explore spin structures on conductive samples, the Spin Polarized-STM (SP-STM) [3][4] is a powerful tool. The SP-STM measures the spin-dependent conductivity between a spin

• -polarized tip and the spin-dependent local density of states of the sample (Figure 1b). STM is unable to probe insulating surfaces but AFM can be used: The antiferromagnetic surface structure of NiO (001) was imaged by Magnetic Exchange Force Microscopy (MExFM) [5]. In MExFM the magnetic exchange force

• 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

Direct-write polymer nanolithography in ultra-high vacuum

• Woo-Kyung Lee,
• Minchul Yang,
• Arnaldo R. Laracuente,
• William P. King,
• Lloyd J. Whitman and
• Paul E. Sheehan

Beilstein J. Nanotechnol. 2012, 3, 52–56, doi:10.3762/bjnano.3.6

• , as illustrated in Figure 4a. Note that the thickness of our films lies intermediate to values reported previously for PDDT on other substrates. Scifo et al. used STM to measure the thickness in UHV of a PDDT film drop cast on highly oriented pyrolytic graphite (HOPG) and reported a film thickness of

• 0.24 ± 0.04 nm [19]. In contrast, Terada et al. [20] reported poly(3-hexylthiophene) (P3HT) on H-terminated Si(100) in UHV to be 0.5 nm thick. Our measured value is closer to the 0.4 nm intermolecular spacing measured for thick films of PDDT [14]. In the prior STM measurements, the measured thickness

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

• , the probe [14] (especially the influence of tunnelling electrons during STM). While in principle NC-AFM can provide a “cleaner” system (i.e., imaging is possible without the presence of tunnelling electrons), a bias is often applied to null out the contact-potential difference (CPD) between tip and

• -temperature (LT) STM/qPlus NC-AFM instrument (Omicron Nanotechnology GmbH) operating in UHV (base pressure ≤ 5 × 10−11 mbar) cooled to 5 K. The sample and tip-preparation procedures are described in detail elsewhere [19][22]. Briefly, boron-doped silicon samples were prepared by standard flash-annealing to

• 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

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• of molecules have not been addressed previously (except for a resonance Auger spectroscopy study [33]), although some results on the structure and molecular packing in the SAMs of nonsubstituted OPE have been reported. In particular, based on STM data, Dhirani et al. reported that the degree of order

• pattern, which was consistent with a 2√3×√3 structure [20]. These results were supported by further STM [34][35] and AFM [36] studies, which reported no ordered structure in OPE2/Au [34] and a high structural order in OPE3/Au [35][36]. However, in contrast to [20], a noncommensurate structure with a

• rectangular unit cell was observed for OPE3/Au in [35], while a basic √3×√3 arrangement was recorded in [36]. Whereas the reasons for the above discrepancies are not clear yet, the molecular packing densities in all three STM/AFM studies [20][35][36] were quite similar and close to those of alkanethiolate (AT

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

• replicated to generate the starting conformation of the SAM is also shown as a black rectangle. It reproduces the periodicity of bright spots in the STM images of [3]. Only the Au atoms of the first surface layer are shown. (b) Snapshot from the MD simulation with the spherical probe (in green) upon the thio

STM study on the self-assembly of oligothiophene-based organic semiconductors

• Elena Mena-Osteritz,
• Marta Urdanpilleta,
• Erwaa El-Hosseiny,
• Berndt Koslowski,
• Paul Ziemann and
• Peter Bäuerle

Beilstein J. Nanotechnol. 2011, 2, 802–808, doi:10.3762/bjnano.2.88

• using scanning tunneling microscopy (STM) at the liquid–solid interface under ambient conditions. The characteristics of the 2-D crystals formed on the (0001) plane of highly ordered pyrolitic graphite (HOPG) strongly depend on the length of the π-conjugated oligomer backbone, on the functional groups

• , is scanning tunneling microscopy (STM). With this method, the self-assembly of oligo- and polythiophenes on surfaces has been successfully investigated in the last few years [5][6][9][10][11][12][13][14]. The 2-D crystalline arrangement on surfaces is a result of a delicate balance between several

• weak intermolecular van der Waals forces and molecule–substrate interactions, as well as intermolecular hydrogen bonding in the case of functionalized oligothiophenes [15][16][17]. The typical flat metallic substrates (HOPG, Au(111), Ag(111), etc.) employed in STM differ from the ITO electrodes used in

Effect of the environment on the electrical conductance of the single benzene-1,4-diamine molecule junction

• Shigeto Nakashima,
• Yuuta Takahashi and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2011, 2, 755–759, doi:10.3762/bjnano.2.83

• conductance of a single benzene-1,4-diamine (BDA) molecule bridging Au electrodes, using the scanning tunneling microscope (STM). The conductance of the single BDA molecule junction decreased upon a change in the environment from tetraglyme, to mesitylene, to water, and finally to N2 gas, while the spread in

• (single-molecule junction) have attracted much attention toward the realization of molecular scale electronics [1][2]. Electrical conductance of the single-molecule junction was investigated by means of mechanically controllable break junction (MCBJ), scanning tunneling microscope (STM), and other

• -molecule junctions were fabricated in an electrochemical cell mounted in a chamber, which was filled with high-purity N2 gas (purity >99.999%) in order to avoid any effects of oxygen and water in the air. The conductance measurements were performed by using electrochemical STM (Pico-SPM, Molecular Imaging

An MCBJ case study: The influence of π-conjugation on the single-molecule conductance at a solid/liquid interface

• Wenjing Hong,
• Hennie Valkenier,
• Gábor Mészáros,
• David Zsolt Manrique,
• Artem Mishchenko,
• Alexander Putz,
• Pavel Moreno García,
• Colin J. Lambert,
• Jan C. Hummelen and
• Thomas Wandlowski

Beilstein J. Nanotechnol. 2011, 2, 699–713, doi:10.3762/bjnano.2.76

• single molecules or of a few molecules trapped between two leads were studied in various experimental platforms. These include scanning tunneling microscopy (STM) [27][28][29], current probe atomic force microscopy (CP-AFM) [30][31][32], scanning tunneling spectroscopy (STS) or STM-break junction (STM-BJ

• indium (EGaIn) [51]. STM-BJ and MCBJ are the two most popular and reliable approaches for single-molecule conductance measurements. Reed et al. [40], Kergueris et al. [41], Reichert et al. [42] and Smit et al. [43] pioneered the MCBJ technique to measure charge transport through single molecules. Xu et

• al. developed an STM-BJ technique based on the formation and breaking of thousands of individual molecular junctions by repeatedly approaching and withdrawing a STM tip towards and away from a substrate in the presence of sample molecules [34]. The MCBJ technique, as compared with the STM-BJ approach

Interaction of spin and vibrations in transport through single-molecule magnets

• Falk May,
• Maarten R. Wegewijs and
• Walter Hofstetter

Beilstein J. Nanotechnol. 2011, 2, 693–698, doi:10.3762/bjnano.2.75

• arises for transport through magnetic atoms embedded in a molecular network on an insulating surface in an STM setup [4][5]. Such systems, which for simplicity we shall refer to as single-molecule magnets (SMM), constitute a single, large spin-moment with spin-anisotropy. The interplay with quantum

• systematic study. We focus on low frequency modes on the scale of the anisotropy parameters, taking Ω = 0.5D, for which the dynamic effects are most pronounced. We note that in STM setups [4][5][6] the anisotropy can be on the meV scale. For the spin value we take the next-to-lowest half-integer value S = 3

STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

• Tibor Kudernac,
• Natalia Shabelina,
• Wael Mamdouh,
• Sigurd Höger and
• Steven De Feyter

Beilstein J. Nanotechnol. 2011, 2, 674–680, doi:10.3762/bjnano.2.72

• localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM). The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid–solid interface. Furthermore, preferential

• patterns with a wide range of symmetries and periodicities [1][2][3][4], with scanning tunnelling microscopy (STM) [7] being a primary characterisation tool. However, combining the ordering of self-organised, physisorbed monolayers with an additional functionality remains an important challenge. In

• attention so far, mostly because they could not be visualised by STM [11][12][13][14]. Here, we report on self-assembly of a neutral shape-persistent macrocycle 1 and its charged analogue 2 (Figure 1) at the interface between an organic solvent and highly oriented pyrolytic graphite (HOPG). We demonstrate

The atomic force microscope as a mechano–electrochemical pen

• Christian Obermair,
• Andreas Wagner and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2011, 2, 659–664, doi:10.3762/bjnano.2.70

• current by the control-voltage-induced movement of just a single atom [4][5][6][7]. In this way, a single-atom transistor was demonstrated as a quantum electronic device operating reproducibly at room temperature. At the same time, the scanning tunneling microscope (STM) and the atomic force microscope

• (AFM) represent techniques that allow surface manipulation on the nanometer scale and even on the atomic scale [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. As shown in Don Eigler’s pioneering work [8], the tip of an STM allows the assembling of structures on a surface, atom by atom. Early

• experiments demonstrated that the tip of an electrochemical STM can also be used for local electrochemical deposition. Material electrochemically deposited on an STM tip was subsequently transferred to the surface [22][23], allowing controlled metallic nanopatterning of surfaces. Improvements of STM-based