Two-dimensional molecular networks at the solid/liquid interface and the role of alkyl chains in their building blocks

• Suyi Liu,
• Yasuo Norikane and
• Yoshihiro Kikkawa

Beilstein J. Nanotechnol. 2023, 14, 872–892, doi:10.3762/bjnano.14.72

• hydrogen atoms of n-dodecane with a trans zigzag conformation are located near the centers of the six-membered rings of C96H24, and the molecule is oriented along one of the lattice directions of C96H24, indicated by the blue arrows. In STM imaging, changes in bias voltage (V) and tunneling current (I

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• , the STM probe tip is positioned back to the initial sample location and the data of the irradiated STM area is acquired. STM imaging and analysis of TPT SAMs on Au(111). (a) Low-magnification STM image (+0.4 V, 70 pA) of a monolayer prepared from DMF-based solution showing α-phases and β-phases as

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• interaction is responsible for the modification of the STM-recorded contrast. One can also note that some molecules are clearly unstable during STM imaging. This makes the identification of the FePc molecules uncertain. In order to unambiguously identify single molecules, a single molecule manipulated and

• contrast mimics differences in the STM contrast. STM imaging conditions: bias voltage −2 V (a, e), tunneling current 100 pA (a, d, e, f). Schematic illustration of the two observed FePc islands on Ge(001):H (top) along with the molecular columns in the α and β phases of FePc (bottom). Images show top views

PTCDA adsorption on CaF₂ thin films

• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1615–1622, doi:10.3762/bjnano.11.144

• experiments were performed under ultrahigh-vacuum conditions. Highly B-doped p-type Si(111) samples (Institute of Electronic Materials Technology, Warsaw, Poland) were used as substrates. The (7 × 7) reconstruction was formed by flash cycles and the (7 × 7) surface quality was checked by STM imaging. CaF2

• in STM imaging of PTCDA/Ag(111) with an s-tip at a bias between −0.4 and −0.5 V [12] and explained by strong domination of the LUMO. In contrast, imaging at larger tip–sample distance and the according loss of sensitivity to intramolecular features was given as an explanation for the prevalently

• calculated molecular orbital shapes with the experimental STM data suggests a strong influence of the LUMO in filled-state STM imaging on the CaF1 interface layer. Instead, the absence of long-range order on the CaF2 films is explained by a mismatch of the common PTCDA motifs with the CaF2 surface structure

Adsorption and self-assembly of porphyrins on ultrathin CoO films on Ir(100)

• Feifei Xiang,
• Tobias Schmitt,
• Marco Raschmann and
• M. Alexander Schneider

Beilstein J. Nanotechnol. 2020, 11, 1516–1524, doi:10.3762/bjnano.11.134

• ), even annealing to 420 K – and, in consequence, metalating – does not improve the molecular ordering of 2 on 1BL CoO. Further heating cannot be applied since oxidation of the molecules sets in. The self-assembled structures of 1 may be identified in detail with the help of bias-dependent STM imaging

Controlling the electronic and physical coupling on dielectric thin films

• Philipp Hurdax,
• Michael Hollerer,
• Larissa Egger,
• Georg Koller,
• Xiaosheng Yang,
• Anja Haags,
• Serguei Soubatch,
• Frank Stefan Tautz,
• Mathias Richter,
• Alexander Gottwald,
• Peter Puschnig,
• Martin Sterrer and
• Michael G. Ramsey

Beilstein J. Nanotechnol. 2020, 11, 1492–1503, doi:10.3762/bjnano.11.132

• : decoupling; integer charge transfer; organic films; para-sexiphenyl; thin dielectric film; Introduction Since the first scanning tunneling microscope (STM) imaging of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of pentacene (5A) on NaCl/Cu(111) was

Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)

• Domenik M. Zimmermann,
• Knud Seufert,
• Luka Ðorđević,
• Tobias Hoh,
• Sushobhan Joshi,
• Tomas Marangoni,
• Davide Bonifazi and
• Willi Auwärter

Beilstein J. Nanotechnol. 2020, 11, 1470–1483, doi:10.3762/bjnano.11.130

• as such spacer layers [18] and can promote site-dependent decoupling and adsorption [19][20], yielding access to optical transitions [21] as well as allowing for orbital-resolved STM imaging [19][21][22][23]. For instance, hBN/Cu(111) [24][25][26][27] features a work function template with a moiré

• , the electronic structure of the functionalized pyrene derivatives 1–3 on hBN/Cu(111) was addressed. Specifically, we performed bias-dependent STM imaging and dI/dV spectroscopy to probe the influence of the substitution, in conjunction with the distinct assemblies, on the molecular electronic states

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

• Jeremiah Croshaw,
• Thomas Dienel,
• Taleana Huff and
• Robert Wolkow

Beilstein J. Nanotechnol. 2020, 11, 1346–1360, doi:10.3762/bjnano.11.119

• presents as a dark depression. A reversed trend is seen in filled states imaging (Figure 2d-2 and Figure 2e-2), with the dihydride side(s) diffusely bright. In constant height STM imaging (Figure 2d-3 and Figure 2e-3), dihydride sites image as areas of reduced current, with neighbouring dimers showing an

• ). STM imaging in Figure 2c-1 and Figure 2c-3 show an enhancement in conductivity at dimers neighbouring the reconstruction and a reduction above the H2Si atoms. Figure 2c-2 shows a dimer row that has been formed between two of the regular dimer rows, with Figure 2c-3 also highlighting this realignment

• the group is pushed during the raster scan. The siloxane dimer of Figure 2h, previously denoted in the literature as a split dimer [77][78] and also incorrectly identified as a dihydride [2][79], is thought to be an oxygen bonded between the two Si atoms of a dimer. STM imaging reveals a localized

Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

• Robby Reynaerts,
• Kunal S. Mali and
• Steven De Feyter

Beilstein J. Nanotechnol. 2020, 11, 1291–1302, doi:10.3762/bjnano.11.113

• solution deposition. Thus, the solution of BA-OC14 was added to the bare HOPG substrate first and the monolayer formed (polymorph A) was imaged for a few hours to ascertain full surface coverage. In the second step, n-C50 solution was added to the surface and the STM imaging was resumed. This experiment

• were found to either grow or shrink upon subsequent STM imaging of the same area. Figure 6b–e shows one such pulse-induced on-command nucleation event. A voltage pulse with a magnitude of −4.2 V lasting 1 ms was applied onto an ‘empty’ region of the n-C50 buffer layer (marked by an arrow in Figure 6c

• deposition and premixing protocols were used. For sequential deposition, a solution of n-C50 was first applied to a freshly cleaved graphite surface. The STM imaging was carried out to ensure full surface coverage of the buffer layer. After this, a drop of BA-OC14 solution was applied and the imaging was

Atomic-resolution imaging of rutile TiO₂(110)-(1 × 2) reconstructed surface by non-contact atomic force microscopy

• Daiki Katsube,
• Shoki Ojima,
• Eiichi Inami and
• Masayuki Abe

Beilstein J. Nanotechnol. 2020, 11, 443–449, doi:10.3762/bjnano.11.35

• performed using Pt-coated Si cantilevers (Budget Sensors, ElectriTAP190G). All cantilevers were cleaned by Ar+ sputtering (0.6 keV, Ar partial pressure of 1.0 × 10−5 Pa, ion current of 0.05 µA, 5 min) before scanning. STM imaging was performed in constant-current mode without cantilever oscillation. NC-AFM

• defect is the same. Previous studies have reported STM imaging visualizing Ti2O3 rows with a bright contrast [22][24][26][28]. Based on these earlier results, the periodic lines with bright contrast in the NC-AFM image can be identified as Ti2O3 rows. STM and NC-AFM provided different geometry

• DFT and STM and to investigate the bias dependence of simultaneous NC-AFM and STM images. This will be discussed elsewhere since the main subject of this article is the periodic line structure on the rutile TiO2(110)-(1 × 2) reconstructed surface. Our NC-AFM and STM imaging in the same area identified

Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower

• Rouzhaji Tuerhong,
• Mauro Boero and
• Jean-Pierre Bucher

Beilstein J. Nanotechnol. 2019, 10, 1243–1250, doi:10.3762/bjnano.10.124

• (b). (d) STM image of the bare Au(111) surface with the MnPc-terminated tip (0.1 nA, −0.3 V). The black arrows indicate the raster-scan direction during the STM imaging process. The scanning speed of the MnPc-terminated MnPc tip over the bare Au(111) surface is 19 nm/s, much slower than the one of 76

Pure and mixed ordered monolayers of tetracyano-2,6-naphthoquinodimethane and hexathiapentacene on the Ag(100) surface

• Robert Harbers,
• Timo Heepenstrick,
• Dmitrii F. Perepichka and
• Moritz Sokolowski

Beilstein J. Nanotechnol. 2019, 10, 1188–1199, doi:10.3762/bjnano.10.118

• molecules are forced into the same planar orientation by the interaction to the metal surface. Further molecules that are deposited onto the compressed first layer possibly form a disordered gas-like second layer on top of this layer. We conclude this because the STM imaging process was strongly disturbed

Capillary force-induced superlattice variation atop a nanometer-wide graphene flake and its moiré origin studied by STM

• Loji K. Thomas and
• Michael Reichling

Beilstein J. Nanotechnol. 2019, 10, 804–810, doi:10.3762/bjnano.10.80

• a solid-liquid STM measurement. Results and Discussion Apart from various defects [5][6][7][8][9], hexagonal superlattices are the most frequently observed planar artefacts found on HOPG(0001) during STM imaging [19][20][21][22]. It was proved by Xhie et al., based on a direct measurement of the

• theory. Note that the capillary force could induce a translation or other type of deformation of the flake and we have no real control over this aspect; however, here the flake was found to be rotated. Superlattices are no rarity, and in fact, this is a common occurrence during STM imaging of bare or

• measurement of Figure 1f, the periodicity is found to be 7.6 nm. Thus, there is a perfect agreement between the periodicities in the model and the STM images of Figure 1e and Figure 1f. The small discrepancy between STM measurements and the calculation could be attributed to thermal drift in STM imaging under

Polymorphic self-assembly of pyrazine-based tectons at the solution–solid interface

• Achintya Jana,
• Puneet Mishra and
• Neeladri Das

Beilstein J. Nanotechnol. 2019, 10, 494–499, doi:10.3762/bjnano.10.50

• of a 100 μM solution of 1 in 1-phenyloctane was drop-cast on a freshly cleaved HOPG surface. The vapor pressure of 1-phenyloctane is sufficiently low to allow for stable STM imaging for several hours. Experiments performed at lower concentrations (10 and 20 μM) did not reveal stable self-assembled

Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy

• Majid Fazeli Jadidi,
• Umut Kamber,
• Oğuzhan Gürlü and
• H. Özgür Özer

Beilstein J. Nanotechnol. 2018, 9, 2953–2959, doi:10.3762/bjnano.9.274

• (CVD) on Cu foils. Truly simultaneous operation is possible only with the use of small oscillation amplitudes. Under a typical STM imaging regime the force interaction is found to be repulsive. Force–distance spectroscopy revealed a maximum attractive force of about 7 nN between the tip and carbon

• topography in this work resulted in maxima in between the two C atoms, which is supported by theoretical calculations. Such an observation would not be possible without simultaneous acquisition of tunnel current and force interaction. Under the typical STM imaging conditions of graphene, the tip–sample

• interaction force is in repulsive regime. This behavior, which has been observed ever since the very early STM results of the HOPG surface, is shown to be the case in graphene surface as well. Hence atomic relaxations might be quite influential in STM imaging of graphene. The contrast mechanisms could be

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

Ester formation at the liquid–solid interface

• Nguyen T. N. Ha,
• Thiruvancheril G. Gopakumar,
• Nguyen D. C. Yen,
• Carola Mende,
• Lars Smykalla,
• Maik Schlesinger,
• Roy Buschbeck,
• Tobias Rüffer,
• Heinrich Lang,
• Michael Mehring and
• Michael Hietschold

Beilstein J. Nanotechnol. 2017, 8, 2139–2150, doi:10.3762/bjnano.8.213

• temperature for 10 min and then the substrate was cooled down to room temperature for STM imaging. DFT calculations were carried out using the grid-based projector augmented wave method (GPAW) [37]. The PBE exchange-correlation functional [38] and the LCAO mode [37] with the standard double-zeta-polarized

• thoroughly investigated. In addition to the imaging, the tunnel tip was active in promoting the reaction by local energy transfer to and local transport of the reactants. Endothermal on-surface reactions of a whole molecular monolayer can be initiated by a corresponding heating process after deposition. STM

• imaging in different stages of the reaction has been demonstrated in such cases where the molecular entities changed their appearance due to structural and electronic changes during different reaction steps. Examples for this are the polymerization reaction of brominated copper-2,3,7,8,12,13,17,18

Non-intuitive clustering of 9,10-phenanthrenequinone on Au(111)

• Ryan D. Brown,
• Rebecca C. Quardokus,
• Natalie A. Wasio,
• Jacob P. Petersen,
• Angela M. Silski,
• Steven A. Corcelli and
• S. Alex Kandel

Beilstein J. Nanotechnol. 2017, 8, 1801–1807, doi:10.3762/bjnano.8.181

• the molecules of the linear dimer row. The spacing in the bulk dimer is 8.5 Å, and thus this feature is packed too closely to represent a planar dimer structure with the binding motif of the bulk crystal. Even accounting for inaccuracy in the STM imaging, the close-packed periodicity should be larger

Comprehensive Raman study of epitaxial silicene-related phases on Ag(111)

• Dmytro Solonenko,
• Ovidiu D. Gordan,
• Guy Le Lay,
• Dietrich R. T. Zahn and
• Patrick Vogt

Beilstein J. Nanotechnol. 2017, 8, 1357–1365, doi:10.3762/bjnano.8.137

• )/(4×4) phase but slightly expanded. Because of the interaction with the Ag(111) substrate, those domains have a very different appearance in STM imaging. The / phase always coexists with the (3×3)/(4×4) and the “” superstructure and forms relatively small domains. Its similarity to the honeycomb (3×3

Ordering of Zn-centered porphyrin and phthalocyanine on TiO₂(011): STM studies

• Piotr Olszowski,
• Lukasz Zajac,
• Szymon Godlewski,
• Bartosz Such,
• Rémy Pawlak,
• Antoine Hinaut,
• Res Jöhr,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2017, 8, 99–107, doi:10.3762/bjnano.8.11

• conditions. Keywords: dye-sensitized solar cells; molecular nanostructures; phthalocyanines; porphyrins; rutile surfaces; STM imaging; Introduction There is an increasing interest in optoelectronic applications of organic molecular heterostructures which utilize inorganic substrates, such as titanium

• Godlewski et al. [19] and Zajac et al. [5] but it seems to be more stable against the STM imaging at room temperature. This indicates that the molecule–substrate interaction related to the Zn central atom is stronger than for Cu-centered phthalocyanine. However, it is not strong enough to hamper the surface

• diffusion necessary for the observed level of surface ordering. Similar ordering is achieved also for coverages slightly exceeding the monolayer (Figure 1, right panel), with additional bright spots attributed to molecules present on top of the wetting layer. High-resolution STM imaging of the ZnPc

Transformations of PTCDA structures on rutile TiO₂ induced by thermal annealing and intermolecular forces

• Szymon Godlewski,
• Jakub S. Prauzner-Bechcicki,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymoński

Beilstein J. Nanotechnol. 2015, 6, 1498–1507, doi:10.3762/bjnano.6.155

• measurements, the sample was cooled to approximately 100 K using a flow cryostat, and the STM imaging was performed in a constant current mode at positive bias voltages (empty state imaging) with etched tungsten tips used as probes. For image processing and STM data analysis, WSxM software was used [42

Nano-contact microscopy of supracrystals

• Adam Sweetman,
• Nicolas Goubet,
• Ioannis Lekkas,
• Marie Paule Pileni and
• Philip Moriarty

Beilstein J. Nanotechnol. 2015, 6, 1229–1236, doi:10.3762/bjnano.6.126

• correlate, in parallel, the dependence of the tunnel current and the tip–sample force on the displacement of the probe. Our combined STM-DFM measurements clearly show that STM imaging of low conductivity supracrystals involves a contact conduction mechanism, and not the through-vacuum tunnelling that is

• height mode over the same region provides additional supporting evidence (inset to Figure 3B), showing a comparable tunnel current image to the previous STM imaging at a tip height −0.5 nm closer to the sample than the constant height DFM imaging shown in Figure 2C. We note that the I(V) characteristics

• nanocrystal supracrystals. We readily obtain single nanocrystal resolution in STM, but are only able to resolve subparticle features by operating in constant height DFM mode. The examination of quantitative short range force spectra reveals that STM imaging occurs not by vacuum tunnelling, but by contact

Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

• Matthew F. B. Green,
• Taner Esat,
• Christian Wagner,
• Philipp Leinen,
• Alexander Grötsch,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 1926–1932, doi:10.3762/bjnano.5.203

• voltage pulses of 3–6 V (applied to the sample) and by crashing 10–30 Å deep into the clean Ag(111) surface whilst simultaneously applying a voltage of 0.1–1 V. The cleanness of the tip was validated by STM imaging of the former lowest unoccupied molecular orbital (LUMO) of PTCDA [10] and spectroscopy of

Probing the electronic transport on the reconstructed Au/Ge(001) surface

• Franciszek Krok,
• Mark R. Kaspers,
• Alexander M. Bernhart,
• Marek Nikiel,
• Benedykt R. Jany,
• Paulina Indyka,
• Mateusz Wojtaszek,
• Rolf Möller and
• Christian A. Bobisch

Beilstein J. Nanotechnol. 2014, 5, 1463–1471, doi:10.3762/bjnano.5.159

• ). After this procedure, the STM imaging proves that the Ge(001) surface exhibits atomically flat terraces with a lateral extension of 30–50 nm and a mixed (2 × 2)/c(4 × 2)-two domain reconstruction pattern as checked by low energy electron diffraction (LEED). We deposited 6 monolayers (MLs) of Au on the