A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• of the HIM, junction barriers of width 1–2 nm were created, that is, narrow enough for the tunneling current to propagate. An overview of the sample and a schematic outlining the irradiation approach are shown in Figure 2d. The electronic properties of the junction barrier can be continuously tuned

Determining amplitude and tilt of a lateral force microscopy sensor

• Oliver Gretz,
• Alfred J. Weymouth,
• Thomas Holzmann,
• Korbinian Pürckhauer and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2021, 12, 517–524, doi:10.3762/bjnano.12.42

• the acquired data. To determine the amplitude and tilt we make use of the scanning tunneling microscopy (STM) channel and acquire data without and with oscillation of the tip above a local surface feature. We use a full two-dimensional current map of the STM data without oscillation to simulate data

• oscillation and tip tilt on the current signal is demonstrated for LFM. Due to the bandwidth of the STM channel, the recorded signal ⟨I⟩ is the average of the current over the motion of the tip [24]: where T = 1/f is the period. I(x, z) is the tunneling current at time τ at the coordinates x and z of the tip

• ⟩ along a line in x-direction over a CO molecule on Cu(111) with a CO tip. The dashed blue curve in Figure 7b is and yielded A = 890 pm ± 2% and θ = 2.00° ± 2%. Conclusion A method of determining the oscillation amplitude and tilt of a LFM sensor was presented by analyzing the tunneling current above a

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

• ) phthalocyanine (FePc) molecules on a Ge(001):H surface results in monolayer islands extending over hundreds of nanometers and comprising upright-oriented entities. Scanning tunneling spectroscopy reveals a transport gap of 2.70 eV in agreement with other reports regarding isolated FePc molecules. Detailed

• ; iron phthalocyanine (FePc); scanning tunneling microscopy; self-assembly; Introduction The development of molecular circuitry requires the preparation of nanostructures isolated from the influence of the underlying substrate. This is of crucial importance for atomic and single-molecule prototypes, but

• single-layer islands extending surprisingly far over distances reaching hundreds of nanometers. Within these islands FePc molecules adopt an upright orientation, which is characteristic for substrates weekly interacting with metal phthalocyanines. Our combined scanning tunneling microscopy (STM) and

TiO_x/Pt₃Ti(111) surface-directed formation of electronically responsive supramolecular assemblies of tungsten oxide clusters

• Marco Moors,
• Yun An,
• Agnieszka Kuc and
• Kirill Yu. Monakhov

Beilstein J. Nanotechnol. 2021, 12, 203–212, doi:10.3762/bjnano.12.16

• scaffold of W3O9 units. By applying scanning tunneling microscopy to the W3O9–(W3O9)6 structures, individual units underwent a tip-induced reduction to W3O8. At elevated temperatures, agglomeration and growth of large WO3 islands, which thickness is strongly limited to a maximum of two unit cells, were

• observed. The findings boost progress toward template-directed nucleation, growth, networking, and charge state manipulation of functional molecular nanostructures on surfaces using operando techniques. Keywords: atom manipulation; scanning tunneling microscopy; supramolecular self-assemblies; titanium

• surfaces by using high-resolution scanning tunneling microscopy (STM), in particular on TiO2(110) [15][16], CuO(110) [17], and Pt(111) [18]. Recently, the surface behavior of W3O9 was assessed on a complex CuWO3 phase grown on Cu(110). The CuWO3/Cu(110) substrate can be viewed as a two-dimensional (2D

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• charging energy. For very weak dot–lead coupling and strong Coulomb interaction, the electrons enter the dot one by one and Coulomb-blockade oscillations of conductance are observed. For stronger coupling to electrodes, higher-order tunneling processes (i.e., cotunneling) begin to play a decisive role

• small-bandgap nanotubes it is parabolic. For wide-bandgap nanotubes, SO splitting can be described by one effective parameter: and describe electrons in the left and in the right electrode, respectively: and the last term in Equation 1 represents tunneling: We parameterize the coupling strength to

Direct observation of the Si(110)-(16×2) surface reconstruction by atomic force microscopy

• Tatsuya Yamamoto,
• Ryo Izumi,
• Kazushi Miki,
• Takahiro Yamasaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2020, 11, 1750–1756, doi:10.3762/bjnano.11.157

• . The pentagonal structure, which is the most important building block of the reconstruction, was concluded to consist of five atoms, while only four or five spots (depending on tip bias) have been reported with scanning tunneling microscopy (STM). Single atoms were determined to exist near step edges

• ], scanning tunneling microscopy (STM) [15][16][17][18][19][20][21][22][23][24], scanning transmission electron microscopy (STEM) [25], and photoelectron spectroscopy (PES) [22][26][27]. The 16×2 reconstruction has a striped structure with upper and lower terraces and with boundaries of monatomic steps. In

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• substrates, thin interfacial films of considerable thickness (5–10 monolayers) of alkali halides have been used in our lab [10]. In contrast, experiments on the light emission from molecules induced by scanning tunneling microscopy (STM-LE) required thin alkali halide films of two monolayers thickness in

• order to support tunneling [11][12][13]. A single layer or films of hBN are attractive for decoupling a molecule from an underlying metal substrate as hBN exhibits a wide bandgap of 5.9 eV [14]. Perspectively, it could also provide a substrate for STM-LE experiments. Furthermore, it is of interest due

• bandgap of hBN, as indicated in Figure 1b. This is in agreement with the findings by Martínez-Galera et al. for PTCDA/hBN/Rh(110) [34]. From scanning tunneling spectroscopy (STS) experiments, the authors concluded that the coupling is only weak. They deduced further that the CT (in the ground state

Detecting stable adsorbates of (1S)-camphor on Cu(111) with Bayesian optimization

• Jari Järvi,
• Patrick Rinke and
• Milica Todorović

Beilstein J. Nanotechnol. 2020, 11, 1577–1589, doi:10.3762/bjnano.11.140

• electronic properties of the material. Assemblies of organic molecules on surfaces have been studied experimentally, for example with X-ray diffraction [4][5], scanning tunneling microscopy [6][7][8] and atomic force microscopy (AFM) [9][10][11]. These methods have a considerable resolution in imaging planar

Optically and electrically driven nanoantennas

• Monika Fleischer,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2020, 11, 1542–1545, doi:10.3762/bjnano.11.136

• low-background medical imaging or nanolasers [33]. Electrically driven optical antennas emit light when a bias voltage is applied to the contacted antenna arms that are forming a tunnel junction. Inelastic electron tunneling through the gap excites gap–plasmon oscillations leading to the emission of

• subject. Energy-level engineering in the gap by introducing molecules into the tunnel junction provides an additional handle to modulate photon emission from an electrically controlled optical antenna. Light emission by tunneling through a single molecule opens the door to combine electronics and quantum

• the feed-gap is shown to couple to propagating modes in waveguides with up to 30% efficiency. Making use of propagating surface plasmon polaritons (SPPs), directional light beams are created in [57]. The SPPs are excited by inelastic tunneling from a scanning probe. The probe is positioned in the

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

• films on Ir(100) by scanning tunneling microscopy (STM) and density functional theory (DFT). The two substrates differ greatly with respect to their structural and potential-energy landscape corrugation with immediate consequences for adsorption and self-assembly of the molecules studied. On both films

• imaged as a protrusion on CoO for tunneling bias voltages of ±2.0 V around the Fermi energy. In Figure 5 we analyze the behavior of 1 on the 2BL CoO film. Imaging of 1 proved difficult at liquid-nitrogen temperatures since the molecules are easily pulled by the STM tip even at junction resistances of RT

• empty-state images. The tunneling current for all images was I = 0.35 nA. The apparent molecular height is indicated in the panels. All images have the same lateral scale and orientation (see (a)), the color scale is non-linear for better visibility. Due to unwanted tip–molecule interactions the

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

• of such decoupling layers may effectively change the electron donating properties of the substrate, for example, by lowering its work function and thus enhancing the charging of the molecular adsorbate layer through electron tunneling. Here, an experimental study of the charging of para-sexiphenyl

• : 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

• layer is not a sufficient condition for decoupling. Although it reduces wave function overlap with the substrate, it can in fact promote charge transfer via tunneling. The determining factor is the energy level alignment of the frontier orbitals of the adsorbate relative to the Fermi level (EF) of the

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

• . Scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of the pyrene derivatives adsorbed on a Cu(111)-supported hexagonal boron nitride (hBN) decoupling layer provided access to spatially and energetically resolved molecular electronic states. We demonstrate that the pyrene electronic gap

• sequential deposition of the cis-like derivative 3 and the trans-like pyrene 2 afforded binary architectures, including regular densely packed arrays and kagome networks hosting the species 3 in the large cavities (Figure S8, Supporting Information File 1). Scanning tunneling spectroscopic measurements Next

• Figures S9 and S10, and the movie in Supporting Information File 2). At bias voltages (see vertical black lines in Figure 5b, 5d, and 5f) where a specific MO could only contribute to the tunneling current in the pore areas, a contrast between the pore and the wire areas emerged in the STM images, with the

Superconductor–insulator transition in capacitively coupled superconducting nanowires

• Alex Latyshev,
• Andrew G. Semenov and
• Andrei D. Zaikin

Beilstein J. Nanotechnol. 2020, 11, 1402–1408, doi:10.3762/bjnano.11.124

• experiments [7][8][9][10]. Likewise, quantum phase slips in superconducting nanowires yield shot noise of the voltage [11] which originates from the process of quantum tunneling of magnetic flux quanta across the wire. One can also proceed beyond the voltage–voltage correlator and evaluate all cumulants of

• and below Rq = 2π/e2 ≃ 25.8 kΩ is the quantum resistance unit and Rjξ is the normal state resistance of the corresponding wire segment), Δ is the superconducting order parameter and a ≈ 1 is a numerical prefactor. We also note that the Hamiltonian (Equation 5) describes tunneling of the magnetic flux

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

• typical building block, namely 4-tetradecyloxybenzoic acid at the 1-phenyloctane–graphite interface in the presence and in the absence of a buffer layer formed by a long chain alkane, namely n-pentacontane. Using scanning tunneling microscopy (STM), three different structural polymorphs were identified

• probe methods, especially scanning tunneling microscopy (STM) [2]. While the formation of structurally diverse crystalline monolayers provides exciting opportunities for surface modification and also for investigating crystal engineering in 2D [5], predicting 2D polymorphism is often nontrivial. The

• ], NaCl [40], CuN [41] and oxides [32][42] have been used. Typically, the ultrathin films of these wide band gap materials act as insulating layers while still allowing electron tunneling through them. Chemisorbed iodine layers have been used as passivating layers on metals such as Au for achieving

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• vacuum. The scanning electron microscope (SEM) was first combined with scanning tunneling microscopy (STM) [2][3], allowing for the visual observation at the tip–sample interaction point with the SEM. Later, Ermakov et al. [4] successfully integrated an AFM into an SEM for the first time, enabling

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• conductive surface, large and constant additional currents relative to a set tunneling current were observed, which varied with the magnitude of the applied bias voltage. These currents occurred regardless of the type of surface (HOPG or Au(111)) or tip material (PtIr, Au or W). The additional currents were

• active acetate instead of chloride axial ligands, the currents remained absent. Keywords: manganese; porphyrins; redox reactions; scanning tunneling microscopy; solid–liquid interface; Introduction Manganese(III) porphyrins are well-known catalysts for the epoxidation of alkenes [1][2][3][4]. The

• single-molecule level, employing scanning tunneling microscopy (STM) [7][8][9]. Since our aim was to stay as close as possible to the laboratory conditions at which catalysis takes place (typically in an organic solvent under ambient conditions), we carried out our STM studies at a solid–liquid interface

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• obtained using the tunneling junction. Hence, any experimental results directly relate to the predictions of the Eliashberg formalism taking into account the effect of vertex corrections. Additionally, in Figure 3d–f we plotted the form of the order parameter on the real axis (T = 4 K). The real part of

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• -temperature scanning tunneling microscopy. Finally, the investigation of the valence band structure by ultraviolet photoelectron spectroscopy shows that the low work function of h-BN/Ni(111) further decreases after the DBP deposition. For this reason, the h-BN-passivated Ni(111) surface may serve as potential

• comprehensive study we utilized differential reflectance spectroscopy (DRS), low-energy electron diffraction (LEED), low-temperature scanning tunneling microscopy (LT-STM), as well as photoelectron spectroscopy (PES). Our results reveal that DBP on h-BN/Ni(111) is well decoupled from the metal substrate Ni(111

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• are due to different molecular vibrational quanta with distinct Huang–Rhys factors. Keywords: graphene; metal surfaces; molecular superstructures; rubrene; scanning tunneling microscopy; scanning tunneling spectroscopy; vibronic states; Introduction Two-dimensional materials are emerging as

• ] and hexagonal boron nitride (h-BN) [3] have been studied in detail. In contrast, vibrational spectroscopy at the single-molecule level is scarce. Scanning tunneling spectroscopy (STS) of vibronic levels of 1,3,5-tris(2,2-dicyanovinyl)benzene on graphene-covered h-BN on SiO2 [4], of cobalt

• -covered Ir(111) [9] have been reported so far. In these studies molecular orbitals, the highest occupied molecular orbital (HOMO) or the lowest unoccupied molecular orbital (LUMO), appear with spectroscopic fine structure in differential conductance (dI/dV, I: tunneling current, V: bias voltage) data

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• vibronic states of an almost isolated molecule. Here, we use scanning tunneling microscopy and spectroscopy to show that a single layer of MoS2 on Ag(111) exhibits a semiconducting bandgap, which may prevent molecular states from strong interactions with the metal substrate. We show that the lowest

• the modes with strong electron–phonon coupling. Keywords: decoupling layer; molybdenum disulfide (MoS2); scanning tunneling microscopy, tetracyanoquinodimethane (TCNQ); vibronic states; Introduction When molecules are adsorbed on metal surfaces, their electronic states are strongly perturbed by

• in a scanning tunneling microscope, requires a metal electrode. To (partially) preserve the molecular properties the molecule–electrode coupling has to be properly designed. An elegant way is to clamp the molecule between electrodes via single-atom bonds at opposing sites of the molecule while the

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• disadvantages. The first approach relies on a continuous current sweep at a constant repetition rate and the measurements of the switching current distributions, from which the response and sensitivity can be determined [14][15][16]. In particular, in [16] the tunneling properties of a current-biased Josephson

• number of absorbed photons and only above-threshold signals can be detected. Also, special care must be taken to minimize the false switching events of the detector due to thermal fluctuations and macroscopic quantum tunneling. In this article the second approach is applied to a prototype of a single

• change the state of the system by switching it to a resistive state with a finite resistance value. At the same time the detector may be triggered spontaneously due to thermal fluctuations in the classical region of temperatures and tunneling through the barrier in the quantum case [15][34]. Experimental

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• , Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland 10.3762/bjnano.11.67 Abstract The adsorption behavior of tin phthalocyanine (SnPc) molecules on rutile TiO2(110) was studied by scanning tunneling microscopy (STM). Low-temperature STM

• tunneling microscopy (STM); tin phthalocyanine (SnPc); titanium dioxide (TiO2); Introduction Phthalocyanines (Pcs) are aromatic molecules that can form metal complexes with a variety of elements, which can be used to tune molecular properties, such as position or shape of adsorption bands. Therefore, Pcs

• rate (0.25 ML/min) was determined using a quartz crystal microbalance. Scanning tunneling microscopy (STM) experiments were performed with the use of either a low-temperature STM (LT-STM) operating at ca. 78 K or a room-temperature STM (RT-STM) manufactured by Scienta Omicron installed in a separate

Templating effect of single-layer graphene supported by an insulating substrate on the molecular orientation of lead phthalocyanine

• K. Priya Madhuri,
• Abhay A. Sagade,
• Pralay K. Santra and
• Neena S. John

Beilstein J. Nanotechnol. 2020, 11, 814–820, doi:10.3762/bjnano.11.66

• microscopy shows enhanced vertical conductance with interconnected conducting domains consisting of ordered monoclinic crystallites through which the charge transfer occurs via tunneling. These results show the importance of a templating layer to induce the formation of a required phase of PbPc suitable for

• indicating that the charge transport in a thin PbPc layer is governed by tunneling (Figure 7). A plot of ln(I/V2) as a function of V−1 indicates a logarithmic dependence in the low-bias region showing direct tunneling, which transforms into a linear dependence in the high-bias region, suggesting Fowler

• –Nordheim (F-N) tunneling or injection tunneling. However, it is seen that the transition from direct to F-N tunneling is not a sharp transition. Instead, there is a seemingly linear slope between the two states. A sharp rise in linear current is noticed beyond this region, which corresponds to F-N

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• atom probe tomography, providing sub-nanometer spatial information of the chemical composition, scanning tunneling electron microscope (STEM) imaging and spectroscopy at low beam energy [65], enabling the characterization of individual defects in h-BN, and atomic electron tomography. However, all these

• of h-BN with triangle shapes. The most commonly formed defects found are boron monovacancies [65] as the dominating zigzag-type edges of the defects are nitrogen terminated. Individual defects with nanoscale resolution were isolated and manipulated by using scanning tunneling microscopy (STM) [95

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• Majid Sanaeepur Department of Electrical Engineering, Faculty of Engineering, Arak University, Arak, 3815688349, Iran Institute of Nanosciences and Nanotechnology, Arak University, Arak, Iran 10.3762/bjnano.11.56 Abstract A nanometer-scaled resonant tunneling diode based on lateral

• substitutional defects (including BC, NC, CB, and CN) at the interface of graphene and boron nitride nanoribbons on the negative differential resistance behavior of the proposed resonant tunneling diode is investigated. Transport simulations are carried out in the framework of tight-binding Hamiltonians and non

• heterojunction; armchair boron nitride nanoribbon (ABNNR); armchair graphene nanoribbon (AGNR); negative differential resistance (NDR); nonequilibrium Green’s function (NEGF); resonant tunneling diode (RTD); substitutional defects; Introduction 2D materials have gained tremendous research interest due to the