Graphene removal by water-assisted focused electron-beam-induced etching – unveiling the dose and dwell time impact on the etch profile and topographical changes in SiO₂ substrates

• Aleksandra Szkudlarek,
• Jan M. Michalik,
• Inés Serrano-Esparza,
• Zdeněk Nováček,
• Veronika Novotná,
• Piotr Ozga,
• Czesław Kapusta and
• José María De Teresa

Beilstein J. Nanotechnol. 2024, 15, 190–198, doi:10.3762/bjnano.15.18

• graphene obtained with the standard Scotch© tape method [1] from highly oriented pyrolytic graphite (HOPG) to take advantage of the lack of residues on top of the graphene layer and the lowest possible amount of defects. Cleaved flakes were deposited onto doped Si with a 285 nm thick SiO2 layer. Optical

• microscope evaluation allowed us to choose flakes that fitted our requirements the best in terms of lateral sizes and number of graphitic layers (optical contrast abruptly changes from monolayer to the bilayer, triple-layer, or HOPG) [37]. The same substrates of separate studies of topographical changes

Dual-heterodyne Kelvin probe force microscopy

• Benjamin Grévin,
• Fatima Husainy,
• Dmitry Aldakov and
• Cyril Aumaître

Beilstein J. Nanotechnol. 2023, 14, 1068–1084, doi:10.3762/bjnano.14.88

• substrate (HOPG). For these tests, the sample was electrically connected to the AWG (channel 1 in Figure 1) by mounting the HOPG substrate onto a sample holder designed with in situ electrical contacts [11]. The results of four measurements with different pump signals are shown in Figure 2. In all cases the

• lower density of non-percolating PC71BM clusters (delaying the SPV decay less). Imaging weak surface photovoltage signals: CsPbBr3 nanosheets on HOPG We have just seen that images of SPV magnitude and dynamics can be obtained with high spatial resolution. In this final section, we will show that DHe

• depositing caesium lead halide perovskite nanosheets (NSs) on a highly oriented pyrolytic graphite (HOPG) substrate. Lead halide perovskites have emerged recently as materials with unique optical and electronic properties, such as high absorption coefficients, high defect tolerance, and charge mobility. Due

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

• flat conducting substrates, such as metal surfaces and highly oriented pyrolytic graphite (HOPG), under ultrahigh vacuum (UHV) conditions, at solid/air or solid/liquid interfaces [23][24][25][26][27][28]. Although UHV-STM offers high-resolution imaging, it requires large, complex, and expensive

• monolayers can be prepared by simply placing the sample solution on a freshly cleaved HOPG surface. The self-assembly at the solid/liquid interface is characterized by the following properties: (i) The correlation between the molecular structure and resultant 2D arrangements can be revealed by STM with high

• the effects of alkyl chains on 2D structure formation at the HOPG/solvent interface and we report some examples of the past decades. We present the effect of the alkyl chain on 2D structure formation either alone or combined with other non-covalent interactions. We then discuss the essential role of

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• periodically in the course of the analysis using Equation 1 by measuring the VCPD value of a freshly exfoliated surface of highly ordered pyrolytic graphite (HOPG) with ϕsample being equal to 4.6 eV [19]. The successively measured ϕtip values showed only small variations with values ranging between 5.65 and

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

• V and +0.4 to +1.2 V. A z-resolution higher than 0.01 nm could be achieved. The STM tips were prepared from 0.375 mm polycrystalline tungsten wire (Alfa Aesar) by electrochemical etching in a 3 M NaOH solution. The instrument was calibrated by imaging HOPG with atomic resolution. The data was post

Sputtering onto liquids: a critical review

• Anastasiya Sergievskaya,
• Adrien Chauvin and
• Stephanos Konstantinidis

Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• ligands attached to the metal center of the porphyrin were observed regardless of the type of surface (highly oriented pyrolytic graphite (HOPG) and Au surfaces were used), solvent (1-phenyloctane and n-tetradecane) and tip material (Pt/Ir, Au, and W), which indicates that the ligands have to be decoupled

Self-assembly of Eucalyptus gunnii wax tubules and pure ß-diketone on HOPG and glass

• Miriam Anna Huth,
• Axel Huth and
• Kerstin Koch

Beilstein J. Nanotechnol. 2021, 12, 939–949, doi:10.3762/bjnano.12.70

• , amorphous substrates. The glasses were cleaned with chloroform before their use in recrystallization studies. Highly oriented pyrolytic graphite (HOPG) was used as non-polar, crystalline substrates (SPI supplies, West Chester, USA). Freshly cleaned HOPG surfaces were prepared by stripping off a layer of

• HOPG with double-sided adhesive tape. Wax extraction from leaves Recrystallization experiments were carried out with a 0.1% (w/v) chloroform (99.8%, ACS reagent, Acros, New Jersey, USA) solution of extracted wax of E. gunnii and a 0.1% (w/v) chloroform solution of ß-diketone. The wax of E. gunnii was

• ). For this, freshly prepared substrates were fixed on a microscope glass slide by double-sided adhesive tape. The ß-diketone solution was applied to glass substrates and the wax solution was applied to glass and HOPG. The measurements were started directly after the evaporation of the bulk of the

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

• formed at the solution–solid interface, is a more of routine occurrence than an exception. Such structurally diverse monolayers are typically formed on solid substrates such as highly oriented pyrolytic graphite (HOPG), graphene, and metals such as Cu, Ag and Au and have been characterized using scanning

• polymorph of hexakis(n-dodecyl)-peri-hexabenzocoronene (HBC-C12) which was not formed when the assembly process was carried out at the n-tetradecane–HOPG interface without the buffer layer [26]. Buffer layers of n-C50 have also been used to ‘select’ certain polymorphs of a Fréchet dendron based on the

• influenced by the symmetry and the structure of the buffer layers. Notably, no self-assembly was observed when CuPc solutions were directly deposited on the HOPG substrate highlighting the role of buffer layers in stabilizing the self-assembled networks [25][31]. Besides their use for influencing structure

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

• mentioned in the introduction was the direct attachment of a gold atom to the manganese center of MnTUPCl, coming from the Au(111) surface below. As a first experiment we therefore decided to also investigate with STM the behavior of MnTUPCl at a HOPG surface instead of a Au(111) surface, since in that case

• organized and dynamic layers were formed on HOPG (not shown). When, however, 1-phenyloctane, a broadly applied aromatic solvent in liquid-STM studies, was used, it was impossible to image the surface or adsorbed molecules regardless of the used surface, due to the occurrence of a large additional increase

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

• rubrene on highly oriented pyrolytic graphite (HOPG) [29]. Our interpretation of the optical spectra is further supported by LT-STM measurements (see Supporting Information File 1, Figure S2) which show a completely filled monolayer as well as molecular clusters on top of the first layer. Lateral

Simulations of the 2D self-assembly of tripod-shaped building blocks

• Łukasz Baran,
• Wojciech Rżysko and
• Edyta Słyk

Beilstein J. Nanotechnol. 2020, 11, 884–890, doi:10.3762/bjnano.11.73

• that for this case the structure reminds of a honeycomb structure, which is the product of the homotactic polycondensation of 1,3-benzene diboronic acid on a HOPG surface [44]. In addition to these MD results, we have performed l-MC simulations. The results for model NT111 agree with the MD results

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

• oriented pyrolytic graphite (HOPG) or SiO2, it has been reported that CuPc attains different orientations resulting in substantial differences in donor–acceptor energy level alignment at the interface. Thus, ordering and orientation of these molecules significantly affect charge carrier injection and

• transport in semiconductor devices [7]. Pristine substrate surfaces of HOPG and Si themselves can induce orientation control over the growth of MPc structures without the aid of additional templating layers. In our earlier work, we have observed that orientation and molecular packing of nonplanar PbPc

• orientation of both planar and nonplanar MPc molecules on oxide substrates such as SiO2 is well known. The molecules were shown to preferably have an edge-on orientation [3][7][9][27][28][29]. In our earlier studies, we have reproducibly obtained different crystallites of PbPc on substrates such as HOPG, Au

Quantitative determination of the interaction potential between two surfaces using frequency-modulated atomic force microscopy

• Nicholas Chan,
• Carrie Lin,
• Tevis Jacobs,
• Robert W. Carpick and
• Philip Egberts

Beilstein J. Nanotechnol. 2020, 11, 729–739, doi:10.3762/bjnano.11.60

• pyrolytic graphite (HOPG) or a KBr crystal to negate the effects of varying scales of roughness, which [12] suggests should be a contributing factor. Qualitatively, there is a general mismatch in behavior when comparing the majority of experimental results with the LJ F(z) curves. In particular, the LJ F(z

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• solid electrolyte interface (SEI) on graphite anodes and HOPG [14][15][16], Li metal [17] and on cathode materials [18][19] as well as the changes in particle size during ageing [19][20]. Other AFM modes used for the analysis of ageing are, for example, Kelvin probe force microscopy (KPFM) and

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• oriented pyrolytic graphite (HOPG) substrate. The sample was electrically connected to the AWG by mounting the HOPG substrate onto a sample holder designed with in situ electrical contacts. The pump signal generated by the AWG was transmitted through a coaxial cable (air side) connected to a twisted pair

• it allows for avoiding topographic artefacts without the need to use a second compensation loop. Single-point spectroscopy measurements performed on HOPG (under electrical pumping) and on an organic solar cell cathode (under optical pumping), confirmed the validity of this implementation. In addition

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• methods and instrumentation All STM measurements were carried out under ambient conditions, using either a Joel JSPM 4210 microscope or an Agilent STM setup, which had been cross-calibrated by imaging HOPG with atomic resolution. The tips were prepared mechanically by cutting a 0.25 mm Pt0.8Ir0.2 wire

Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC₇₁BM-based organic photovoltaic cells

• Olivia Amargós-Reyes,
• José-Luis Maldonado,
• Omar Martínez-Alvarez,
• María-Elena Nicho,
• José Santos-Cruz,
• Juan Nicasio-Collazo,
• Irving Caballero-Quintana and
• Concepción Arenas-Arrocena

Beilstein J. Nanotechnol. 2019, 10, 2238–2250, doi:10.3762/bjnano.10.216

• acquired with a JEOL JSM 7800F. STM [32][33] measurements were carried out under ambient conditions with the Nanosurf Easyscan 2 STM device. For the latter measurements, FeS2 was dissolved in chlorobenzene at a concentration of 0.2 mg/mL and deposited on a highly ordered pyrolytic graphite (HOPG) surface

• by drop casting. Mechanically cut Pt–Ir wires were used as STM tips. Before the deposition of each film, HOPG substrates were cleaved by using the adhesive tape technique to obtain an atomically clean surface. Cyclic voltammetry (CV) measurements were carried out using a PARSTAT 2273 potentiostat in

• structure of PTB7 and PC71BM. a) and b) TEM images of the FeS2 NCs at the 50 and 100 nm scale and c) size distribution of the NCs. a) STM image of FeS2 deposited on HOPG substrate (thickness ≈20 nm) with 50 nm × 50 nm scan size and b) SEM image of FeS2 NCs (scale bar = 100 nm). a) Cyclic voltammograms of

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• following study [37]. The CPD resolution at the TiO/SrTiO3 transition is insensitive to the nanowire height, following the same asymptotic behavior (see Figure 4d), unlike the situation for C60 islands on HOPG, where a spread of 50 nm was reported, while the topography resolution was 10 nm [38]. From our

• STO materials enabled a low sample bias of +1 mV for the LC-AFM measurements to be used. Real work function values were calculated from recorded CPD maps after calibration against a material of known work function, here highly oriented pyrolytic graphite (HOPG), which was annealed in situ up to 300 °C

• in order to remove water and other adsorbates. After each set of KPFM measurements, the HOPG surface was scanned employing the same experimental parameters and a VCPD(HOPG) was obtained. Assuming a HOPG work function of ϕHOPG = 4.5 eV (subject literature values: 4.6 ± 0.1 eV [57], 4.4 ± 0.1 eV [58

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• material because of its well-defined layered structure with sub-nanometer roughness similar to mica or highly oriented pyrolytic graphite (HOPG). The electrical conductivity and mechanical stiffness of Bi2Se3 allow for the measurement with high-intensity electrical fields (10 V/30 nm) without damaging the

Nanoscale spatial mapping of mechanical properties through dynamic atomic force microscopy

• Zahra Abooalizadeh,
• Leszek Josef Sudak and
• Philip Egberts

Beilstein J. Nanotechnol. 2019, 10, 1332–1347, doi:10.3762/bjnano.10.132

• modulus of highly oriented pyrolytic graphite (HOPG), specifically by using force modulation microscopy (FMM) and contact resonance (CR) AFM. In both of these techniques, a variation in the amplitude signal was observed when scanning over an uncovered step edge of HOPG. In comparison, no variation in the

• (CR) AFM; elastic modulus mapping; force modulation microscopy (FMM); highly oriented pyrolytic graphite (HOPG); mechanical properties; surface science; surface steps; Introduction In recent years, the study of the size-dependent properties of materials, and in particular those at the nanometer scale

• vacuum (UHV) AFM, which can increase the spatial resolution of the measured mechanical properties as well as the reliability of the measurements made. In this work, both FMM and CR modes have been employed to examine surfaces of highly oriented pyrolytic graphite (HOPG) under UHV conditions in order to

In situ AFM visualization of Li–O₂ battery discharge products during redox cycling in an atmospherically controlled sample cell

• Kumar Virwani,
• Younes Ansari,
• Khanh Nguyen,
• Francisco José Alía Moreno-Ortiz,
• Jangwoo Kim,
• Maxwell J. Giammona,
• Ho-Cheol Kim and
• Young-Hye La

Beilstein J. Nanotechnol. 2019, 10, 930–940, doi:10.3762/bjnano.10.94

• Li/O2 reactions. Wen et al. [23] performed in situ AFM imaging of the Li/O2 electrochemical reaction on highly oriented pyrolytic graphite (HOPG). In their work, the imaging during the electrochemical reaction was performed using contact mode and upon completion of the electrochemical reaction, the

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

• sufficient to account for the total expenditure of energy involved in the process. Keywords: capillary force; graphene; graphite; HOPG; moiré; solid–liquid interface; STM; superlattice; Introduction Graphite is a layered material with graphene sheets arranged in ABAB stacking. HOPG is an ordered form of

• pyrolytic graphite with a high degree of crystallographic orientation of the c-axis. Polycrystalline HOPG consists of micrometer-sized grains and has been widely used as a substrate in STM studies [1][2][3] due to its high conductivity, atomic flatness and chemical inertness [4]. The surface also contains

• 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

Self-assembly and wetting properties of gold nanorod–CTAB molecules on HOPG

• Imtiaz Ahmad,
• Floor Derkink,
• Tim Boulogne,
• Pantelis Bampoulis,
• Harold J. W. Zandvliet,
• Hidayat Ullah Khan,
• Rahim Jan and
• E. Stefan Kooij

Beilstein J. Nanotechnol. 2019, 10, 696–705, doi:10.3762/bjnano.10.69

• drying on a nonwetting highly ordered pyrolytic graphite (HOPG) surface have been investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Although SEM did not reveal coverage of CTAB layers, AFM showed not only CTAB assembly, but also the dynamics of the process on the

• surface. The self-assembled layers of CTAB molecules on the HOPG terraces prior to nanorod deposition were shown to change the wettability of the surface, and as a result, gold nanorod deposition takes place on nonwetting HOPG terraces. Keywords: CTAB; gold nanorods; micelles; self-assembly; wettability

• that CTAB surfactant molecules can self-assemble on a highly ordered pyrolytic graphite (HOPG) surface in the form of hemi-cylindrical micelles [43][44][45]. The surface of HOPG is hydrophobic [46][47], while the CTAB molecules have a hydrophilic end group and a hydrophobic tail [48]. Therefore, to

Mechanical and thermodynamic properties of Aβ₄₂, Aβ₄₀, and α-synuclein fibrils: a coarse-grained method to complement experimental studies

• Adolfo B. Poma,
• Horacio V. Guzman,
• Mai Suan Li and
• Panagiotis E. Theodorakis

Beilstein J. Nanotechnol. 2019, 10, 500–513, doi:10.3762/bjnano.10.51

• , such as highly oriented pyrolytic graphite (HOPG), silica, and other “clean” surfaces, which are, however, very far away from biological systems. Moreover, by considering the indenter as a sphere, the anisotropies in the deformed material can be screened, since the measured deformation depends on the