(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• voltages higher than 1.5 V were applied and also a sudden conversion between 1 and 2 was observed. It is possible to control the interconversion between 1 and 2 by the STM tip. A typical case is shown in Figure 10a–e, where the tip is positioned over a molecule and the only the bias voltage is modified

• from [44], copyright 2014 Elsevier. (a–e) Manipulation of the electronic structure by applying a voltage pulse with the STM tip at the position marked with a white circle. Converted molecules are marked with green (1→2) or blue (2→1) rectangles. (a–c) 1→2→1 conversion with 2 V pulses for 3 s (feedback

Transport characteristics of a silicene nanoribbon on Ag(110)

• Ryoichi Hiraoka,
• Chun-Liang Lin,
• Kotaro Nakamura,
• Ryo Nagao,
• Maki Kawai,
• Ryuichi Arafune and
• Noriaki Takagi

Beilstein J. Nanotechnol. 2017, 8, 1699–1704, doi:10.3762/bjnano.8.170

• SiNR on Ag(110). To isolate SiNR from the Ag substrate, we lift up an individual SiNR with the tip of a low-temperature scanning tunneling microscope (STM) and fabricate a nanojunction in which the lifted SiNR bridges the gap between the STM tip and the substrate. This method enables us to isolate the

• results are nicely matched with those reported in the previous STM works [25][26]. We measured dI/dV spectra as a function of the STM tip location. Figure 2a,b shows the spectra measured in the narrow and wide voltage ranges. One sees that these spectra are very similar to each other and do not depend on

• interaction of SiNRs with the substrate may hamper the emergence of intrinsic electronic features of freestanding SiNR. To reveal the intrinsic electronic features of SiNRs, we conducted transport measurements for individual SiNRs by lifting up each SiNR with the STM tip and fabricating a nanojunction

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• tunnel current is measured, marking the jump of the molecule to the tip apex. A pentacene-functionalized STM tip might express a considerably smaller effective tip apex due to scanning with one of the π-orbitals of the attached pentacene molecule and thereby improves spatial resolution. Using a

• , constant height). Spatial mapping of the molecular orbitals of pentacene by employing an STM tip without (left) and with (right) pentacene functionalization (U(LUMO) = +1.2 V, U(HOMO) = −2.1 V, I = 50 pA, constant height). Hückel calculations of the frontier molecular orbitals (HOMO and LUMO) of pentacene

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

• molecular structures were unstable against the STM tip, precluding any high-resolution imaging. It was found, however, that this situation could be greatly improved if the wetting layer of the native CuPc molecules was substituted by Zn(II)meso-tetraphenylporphyrins (ZnTPP) [5]. The present work extends

• chains parallel to the [01−1] direction have been found and explained in our previous work on CuPc molecules [18]. At low coverage the molecules are perturbed by the scanning STM tip, causing a repetitive movement between the same surface barrier points during subsequent scans, such as surface hydroxy

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• move ZnEP molecules in both conformations with the STM tip in order to change their distance from neighbouring oxygen vacancies. These manipulation events were accompanied with scanning tunnelling spectroscopy measurements revealing the significant influence of oxygen vacancies on the position of the

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34

• STM tip resonantly tunnels into an excited state of the porphyrin molecule 38 strongly bounded to the gold surface, and the excited molecule then decays radiatively back to the ground

Effects of spin–orbit coupling and many-body correlations in STM transport through copper phthalocyanine

• Benjamin Siegert,
• Andrea Donarini and
• Milena Grifoni

Beilstein J. Nanotechnol. 2015, 6, 2452–2462, doi:10.3762/bjnano.6.254

• molecule is put on a thin insulating layer grown on top of a conducting substrate. The layer functions as a tunneling barrier and decouples the molecule from the substrate. Hence the CuPc molecule acts as a molecular quantum dot weakly coupled by tunneling barriers to metallic leads (here the STM tip and

High electronic couplings of single mesitylene molecular junctions

• Yuki Komoto,
• Shintaro Fujii,
• Tomoaki Nishino and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2015, 6, 2431–2437, doi:10.3762/bjnano.6.251

• before use. Then the Au substrate was fixed in a Teflon liquid cell with the Viton O-ring. Pure mesitylene solvent was poured into the cell. STM-BJ experiments were performed as reported previously. The STM tip was prepared by mechanically cutting Au wire (diameter = 0.3 mm, purity >99%) [45]. In the I–V

• experiments, the STM tip was approached to the substrate until a metal junction with conductance of 6.5G0 was formed in air at room temperature. Subsequently, the tip was withdrawn for 10 nm at a tip speed of 38 nm/s to break the Au junction and to prepare the molecular junction. The tip was held and the bias

Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules

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

Beilstein J. Nanotechnol. 2015, 6, 2148–2153, doi:10.3762/bjnano.6.220

• cameras that compose an image from which the VICON software reconstructs the position and the orientation (not used in the experiment) of the Apex device in 3D space. The obtained coordinates x,y,z are used to set the position of the AFM/STM tip. The same coordinates are used to plot 3D trajectories in

Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

• Yuya Kitaguchi,
• Satoru Habuka,
• Hiroshi Okuyama,
• Shinichiro Hatta,
• Tetsuya Aruga,
• Thomas Frederiksen,
• Magnus Paulsson and
• Hiromu Ueba

Beilstein J. Nanotechnol. 2015, 6, 2088–2095, doi:10.3762/bjnano.6.213

• (STM), we demonstrated a molecular switch made functional by the mechanical motion of a phenyl ring, which is the atomic-scale analogue of the conventional toggle switch. A phenoxy (C6H5O, PhO) molecule bonded to the Cu(110) surface was reversibly lifted (released) to (from) the STM tip while being

• -temperature STM was used to image and manipulate individual phenoxy (PhO) and thiophenoxy (PhS) molecules on Cu(110). These species are strongly bonded to the surface via the chalcogen atom in a nearly flat configuration. By moving the STM tip towards a target molecule or by applying a voltage pulse over it

Distribution of Pd clusters on ultrathin, epitaxial TiO_x films on Pt₃Ti(111)

• Christian Breinlich,
• Maria Buchholz,
• Marco Moors,
• Tobias Pertram,
• Conrad Becker and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2015, 6, 2007–2014, doi:10.3762/bjnano.6.204

• the measured particle diameter is actually the result of a convolution between the true particle size and the STM tip shape [14]. The actual particle diameter is smaller, but the distribution obtained for different coverages and the two different substrates still allow for comparison. Regarding the

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• -contact” method [23][24][30][44][45]. The “STM touch-to-contact” method requires the STM tip to be positioned immediately above and just touching the LB film, avoiding both penetration of the STM tip into the film or a significant gap between the STM tip and the monolayer. This in turn requires

• tunneling parameters (I0 = 60 nA and Ut = 0.6 V) so that the tip approaches relatively close to the surface and is thereby embedded within the LB film. From these set-point conditions the STM tip was then rapidly retracted while monitoring the current decay with distance. Only current–distance retraction

• similar molecular films of highly conjugated organic compounds [23][24][30][45][98][99] and for single molecules [15][100][101]. The dlnI/ds value for the LB film is used in conjunction with Equation 2 and an extrapolation to the conductance value corresponding to the point where the gold STM tip contacts

Closed-loop conductance scanning tunneling spectroscopy: demonstrating the equivalence to the open-loop alternative

• Chris Hellenthal,
• Kai Sotthewes,
• Martin H. Siekman,
• E. Stefan Kooij and
• Harold J. W. Zandvliet

Beilstein J. Nanotechnol. 2015, 6, 1116–1124, doi:10.3762/bjnano.6.113

• also been applied to tunneling junctions consisting of a single molecule attached to both the STM tip and the sample and to tip-molecule-vacuum-sample junctions [27][41][42]. While a non-unity effective mass does indeed lead to lower apparent barrier heights, the tip–vacuum–sample system described in

Chains of carbon atoms: A vision or a new nanomaterial?

• Florian Banhart

Beilstein J. Nanotechnol. 2015, 6, 559–569, doi:10.3762/bjnano.6.58

• STM [42]. Oligoynes functionalized with anchor groups have been contacted by an STM tip, in part in solution. However, it is unclear whether individual monoatomic chains without side-links to other molecules have been present between the anchors and served as conductivity-limiting molecular junctions

Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes – a new strategy for OLED materials

• Pascal R. Ewen,
• Jan Sanning,
• Tobias Koch,
• Nikos L. Doltsinis,
• Cristian A. Strassert and
• Daniel Wegner

Beilstein J. Nanotechnol. 2014, 5, 2248–2258, doi:10.3762/bjnano.5.234

• sickle-like features with lower intensity to the bottom right. The simultaneously recorded topography (not shown here) looks similar to that of Figure 6a. Therefore it is unclear whether this asymmetry is an artifact caused by the STM tip. Essentially, despite the bulky tert-butyl groups, the dI/dV maps

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

• used a qPlus sensor [17] manufactured by CREATEC. The AFM/STM tip was made from a 0.3 mm long and 15 μm thick PtIr wire glued to the tuning fork of the qPlus sensor, and sharpened with a gallium focused ion beam (FIB). The resulting resonance frequency of the qPlus sensor was f0 = 30,300 Hz with a

• strength of the method derives from the direct manual control of the AFM/STM tip. This allows the operator to explore the unknown potential in the state space of the manipulated system, quickly determining the manipulation trajectories that steer the system into the desired final state(s). By using HCM we

• were able to find the trajectories of the AFM/STM tip that break the intermolecular bonds in the molecular monolayer of PTCDA/Ag(111) and write the first ever complex structure with large molecules. The HCM method reported here brings us a step closer to the possibility of building functional nanoscale

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

• current. A third STM tip simultaneously measures the topography and the potential of the surface between the contacts [13][14][15]. The STP experiments were carried out at a base pressure below 3 × 10−10 mbar for various sample temperatures between 130 K and 300 K. In order to establish smooth contacts to

• corresponds to the potential underneath the STM tip. This allows us to map the potential with atomic precision. To maintain a tunnelling distance between the STM tip and the sample surface, we additionally apply a small alternating tunnelling voltage (Vmod) such that the tip/sample distance can be controlled

• ) Scheme of the potentiometry setup using a multiprobe STM. Two STM tips (1 and 2) in contact with the sample surface are used to drive a lateral current. The third STM tip (3) simultaneously images the topography and the electrochemical potential of the surface. b) HRSEM image of the 6 ML Au/Ge(001

Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

• Adam Sweetman and
• Andrew Stannard

Beilstein J. Nanotechnol. 2014, 5, 386–393, doi:10.3762/bjnano.5.45

• indentation of the tip into the surface will require the tip structure checks to be repeated. This is likely to be even more important in the case of experiments using qPlus-type setups, where STM tip treatment methods are often used to prepare tips in situ on the surface. In these cases, significant transfer

Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond

• Cai Shen and
• Manfred Buck

Beilstein J. Nanotechnol. 2014, 5, 258–267, doi:10.3762/bjnano.5.28

• , the phase transition involved in the annealing is another process likely to contribute as discussed further below. Defects in the SAM are introduced by pulsing the STM tip. The extent of damage depends on the voltage, and a value of 4.5 V was used in this example, which generates defects about 6 nm in

• demonstrates that these Cu patterns were formed by the Cu2+ ions diffusing radially out from the defects initially created by the STM tip. Ultimately the island coalesce to form a uniform UPD area (Figure 3e), which in the example displayed was accomplished after 486 min at 200 mV. In order to make the uniform

• image of the surface before deposition recorded in air. (b) Magnified image of area marked in (a) revealing an array of point defects created by voltage pulses of 4.5 V applied to the STM tip for 50 ms. Steps in the Au substrate are highlighted by the arrows. Dashed circles mark defects at the edge of a

STM tip-assisted engineering of molecular nanostructures: PTCDA islands on Ge(001):H surfaces

• Amir A. Ahmad Zebari,
• Marek Kolmer and
• Jakub S. Prauzner-Bechcicki

Beilstein J. Nanotechnol. 2013, 4, 927–932, doi:10.3762/bjnano.4.104

Adsorption of the ionic liquid [BMP][TFSA] on Au(111) and Ag(111): substrate effects on the structure formation investigated by STM

• Benedikt Uhl,
• Florian Buchner,
• Dorothea Alwast,
• Nadja Wagner and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 903–918, doi:10.3762/bjnano.4.102

• protrusion appears with lower height, which is due to the parts of the alkyl ring that are not directly lying below the butyl chain. In the measured STM images, only the round shaped protrusion is visible due to the limited resolution of the STM tip. The anion appears in the simulated images as two longish

Ni nanocrystals on HOPG(0001): A scanning tunnelling microscope study

• Michael Marz,
• Keisuke Sagisaka and
• Daisuke Fujita

Beilstein J. Nanotechnol. 2013, 4, 406–417, doi:10.3762/bjnano.4.48

• [7][8]. Various methods are employed for growing metallic clusters on surfaces such as ion sputtering [9], pulsed laser deposition [10], electro deposition [11][12][13], vapor deposition [14], aerosol deposition [15], material transfer of an STM tip [16], etc. For the formation of nanoparticles a

• pick up individual clusters with the STM tip in a controlled way. One demonstration of the pick-up is given in Figure 7 with topographic STM images before (a) and after (b) the picking up of the cluster. The basic idea of the process is based on gradually reducing the cluster–tip distance, until the

• surface. Finally, controlled picking-up of individual Ni clusters with the STM tip has been described. Evaporation time and flux dependence of the growth of the Ni-clusters without further annealing. STM topographic images of (a) freshly cleaved HOPG. The image shows a large-scale scan (V = 2 V; I = 0.2

Revealing thermal effects in the electronic transport through irradiated atomic metal point contacts

• Bastian Kopp,
• Zhiwei Yi,
• Daniel Benner,
• Fang-Qing Xie,
• Christian Obermair,
• Thomas Schimmel,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 703–711, doi:10.3762/bjnano.3.80

• expansion on a laser-irradiated metallic nanocontact has been demonstrated already some time ago in scanning tunnelling microscopy (STM) experiments [19][20]. Upon irradiating the STM tip with a short laser pulse, the junction resistance was observed to be drastically reduced due to the expansion of the tip

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

• bare HOPG substrate was imaged to ensure the quality of the STM tip and the cleanliness of the substrate surface. By imaging the atomic structure of the bare graphite, the scanner was calibrated at regular time intervals so that the precision of measurements was solely limited by thermal drift. The

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

• 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

• nanostructures [10][11][12][13][14][15][16][17]. Direct magnetic interactions between STM tip and magnetic materials on a substrate have been studied in a number of works [18][19][20], and STM has been used to probe spin in organic molecules [21]. In the case of a magnetic tip and magnetic surfaces, this method

• spin-filtering and spin-valve effects in STM experiments. System setup and methods In order to mimic a concrete STM experiment, we investigated the specific setup shown in Figure 1. The bulk regions of the contacts (i.e., STM tip and substrate) have been chosen to be nonmagnetic copper, which has