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

• of the substrate, for instance by adding or intercalating a decoupling layer, are often the better choice. In the best case, these interfacial layers have a large bandgap to prevent a hybridization with molecular states as well as with the metallic/semiconducting substrate. All the strategies for

• physical and electronic decoupling have been developed in view of fundamental studies as well as application in devices. Ultrathin semiconducting or insulating decoupling layers can be epitaxially grown as mono- and multilayers on many metallic substrates by either physical or chemical vapor deposition

• . Among others, ultrathin dielectric layers of either alkali halides (e.g., NaCl [17]) or metal oxides (e.g., MgO [18], Al2O3 [19], and CuO [20]), or nitrides (CuN [21]) have been shown to be beneficial for successfully reducing or even completely switching off the unwanted interaction between the metal

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

• least 2% of diols [25]. The expected arrangements of the tubule-forming molecules are bended layers of nonacosanol and alkanediol. Within these layers, the hydroxyl groups of the alcohol molecules function as spacers in the tightly packed layer, leading to a curvature of the layer and eventually to the

• amplitude data of AFM measurements were processed and analyzed with JPK data processing software (version 4.2.62). The height of the tubules and the thickness of the layers were investigated using the cross section function of the processing software. The tubule height was calculated by averaging the height

• differences between the maximum tubule length to the left-side base and to the right-side base of the tubule. The height growth velocity of the tubules was calculated by linear regression lines of the height values as a function of time. The thickness of the layers (n = 10) was measured by the mean value of

The role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

• Nabojit Das,
• Akash Kumar and
• Raja Gopal Rayavarapu

Beilstein J. Nanotechnol. 2021, 12, 924–938, doi:10.3762/bjnano.12.69

• ]. The difference between the electrochemical double layers and a differential activity of chloride ions (i.e., preferential facet binding during crystal growth restricting the lattice growth in a particular direction) were responsible for the observed morphological difference. The lower surface tension

In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures

• Olena M. Kapran,
• Roman Morari,
• Taras Golod,
• Evgenii A. Borodianskyi,
• Vladimir Boian,
• Andrei Prepelita,
• Nikolay Klenov,
• Anatoli S. Sidorenko and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 913–923, doi:10.3762/bjnano.12.68

• demonstrate how FORC can be used for detailed in situ characterization of magnetic states. It reveals that upon reduction of the external field, the magnetization in ferromagnetic layers first rotates in a coherent scissor-like manner, then switches abruptly into the antiparallel state and after that splits

• relative orientation of magnetizations in several F-layers [18][19][22][23][25][26][27][28][29][30][31][32][33][34][35]. However, the practical realization of such devices is complicated because neither ways of controlling many degrees of freedom in S/F multilayers, nor methods for monitoring magnetic

• microstructured Nb/Co multilayers (MLs) with a different number of F-layers and layer thicknesses. Our goal is to demonstrate how conventional experimental techniques can be used for in situ assessment of magnetic states of small S/F devices. The key technique that we employ is the first-order-reversal-curves

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu²⁺ ions

• Bahdan V. Ranishenka,
• Andrei Yu. Panarin,
• Irina A. Chelnokova,
• Sergei N. Terekhov,
• Peter Mojzes and
• Vadim V. Shmanai

Beilstein J. Nanotechnol. 2021, 12, 902–912, doi:10.3762/bjnano.12.67

• deposited onto a PEI-modified silicon conductive support by adsorptive immobilization. Immobilization kinetics of Ag NPs on a glass substrate. Since the glass slides were modified on both sides, the spectra correspond to the absorption of two NPs layers. SEM image of Ag NPs immobilized on silicon surface by

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

• boundary line in Figure 1). Then, a non-linear function is applied for each neuron. Without this step, termed “activation” (see below), multiple layers add no new knowledge to the problem. This non-linear function enables the neural network to learn complex non-linear decision boundaries instead of the

• linear decision boundaries, and prevents it from collapsing to a neural network without hidden layers. Application of this linear decision boundary has no benefit over logistic/linear regression, which is used for classification/regression in supervised machine learning. The weights and biases are

• , and pooling layers together form an operation block. Usually, this block is applied several times. Each block corresponds to a hidden layer. The number of filters can be increased or remain the same in each successive block, and the feature maps are down-sampled leading to dimension reduction while

Effects of temperature and repeat layer spacing on mechanical properties of graphene/polycrystalline copper nanolaminated composites under shear loading

• Chia-Wei Huang,
• Man-Ping Chang and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2021, 12, 863–877, doi:10.3762/bjnano.12.65

• ]. Therefore, the design of ordered graphene composites and the development of optimized microstructures is a major issue to study. In 2013, Kim et al. synthesized metal–graphene nanolayered (MGNL) composites consisting of alternating metal (copper or nickel) layers and graphene monolayers [22]. Since then, a

• the mechanical properties of carbon materials [31]. In this study, graphene with zigzag and armchair chirality is considered while simulating different properties of graphene monolayers and copper layers, including stress–strain curve variations, the distribution of von Mises stress, the evolution of

• specific strain. In the case of the GPCuNL composite at 300 K, the shear stress drops suddenly when the strain is 0.39. Because the two layers of graphene do not fracture at the same time, a plateau appears in the curve followed by another drop at γ = 0.415, indicating another graphene failure. Furthermore

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material

• Yuri B. Matos,
• Rodrigo S. Romanus,
• Mattheus Torquato,
• Edgar H. de Souza,
• Rodrigo L. Villanova,
• Marlene Soares and
• Emilson R. Viana

Beilstein J. Nanotechnol. 2021, 12, 798–807, doi:10.3762/bjnano.12.63

• smaller than that of the silver peaks, suggesting no stacking of halloysite layers in the composite. Figure 4 shows TEM images of halloysite substrate samples and of samples that went through the thermal reduction of silver. Images of HNT-0, HNT-4, and HNT-8 (Figure 4a,c,e) show that the NaOH treatment

Reducing molecular simulation time for AFM images based on super-resolution methods

• Zhipeng Dou,
• Jianqiang Qian,
• Yingzi Li,
• Rui Lin,
• Jianhai Wang,
• Peng Cheng and
• Zeyu Xu

Beilstein J. Nanotechnol. 2021, 12, 775–785, doi:10.3762/bjnano.12.61

• Lennard–Jones (LJ) potential is used to describe the interaction between the graphene layers and the tip substrate. The LJ parameters for C–C are εC–C = 2.84 meV, σC–C = 0.34 nm and for Si–C the parameters are εSi–C = 8.909 meV, σSi–C = 0.3326 nm (ε is the depth of the potential well, σ is the finite

• SRCNN is a representative method for deep learning super-resolution techniques and consists of three layers. This method uses bicubic interpolation as the preprocessing step and, then, extracts overlapping image blocks as high-dimensional vectors with the same dimension as the feature image through

• to reconstruct the complete image. The flow chart of the proposed SRCNN reconstruction method. First, the low-resolution simulated image is obtained, then the SRCNN method is used to reconstruct the high-resolution image. The SRCNN consists of three layers to implement feature extraction, non-linear

9.1% efficient zinc oxide/silicon solar cells on a 50 μm thick Si absorber

• Rafal Pietruszka,
• Bartlomiej S. Witkowski,
• Monika Ozga,
• Katarzyna Gwozdz,
• Ewa Placzek-Popko and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 766–774, doi:10.3762/bjnano.12.60

• inexpensive alternatives for indium tin oxide (ITO) [9]. In this work, we used ALD to deposit zinc oxide nanoseeds, magnesium-doped zinc oxide (MZO) layers and aluminium-doped zinc oxide films. We thus continue our interest on photovoltaic structures based on thin films of ZnO. Recently, there have been

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• with different magnetisms with applications in, for example, energy-saving logic, sensors, environmental remediation, and data storage [52]. Chen et al. [53] studied compensated magnetic heterostructures containing ferrimagnetic CoGd alloys and antiferromagnetic IrMn layers. The terahertz emission from

Prediction of Co and Ru nanocluster morphology on 2D MoS₂ from interaction energies

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2021, 12, 704–724, doi:10.3762/bjnano.12.56

• made up of two layers. To create the pristine ML one of these was removed, which also creates the vacuum necessary to avoid interaction along the z-axis; the vacuum region is 8 Å. A (5 × 5) super cell was used. No van der Waals (vdW) corrections were applied, as both the literature and our own tests

Electromigration-induced formation of percolating adsorbate islands during condensation from the gaseous phase: a computational study

• Alina V. Dvornichenko,
• Vasyl O. Kharchenko and
• Dmitrii O. Kharchenko

Beilstein J. Nanotechnol. 2021, 12, 694–703, doi:10.3762/bjnano.12.55

• according to the Stransky–Krastanov growth regime [16][17][18][19], whereas at elevated temperatures such processes are associated with the solid dissolution of the layers of precipitated material [20][21]. Surface EM [22][23] is widely used in the study of thin solid films, for example, for the formation

• leading to a growth of multilayer adsorbate islands due to pairwise attractive interaction between adatoms. In such a case the reaction term R(x) should take into account the term ft responsible for the transitions of adatoms between neighboring layers, representing vertical diffusion. These transitions

• computed by solving the appropriate electrostatic boundary value problem [74]. In the present study we aimed to analyze a change in the morphology of the thin film on a substrate (first growing layer), assuming that upper layers will repeat the morphology of the first one. In this connection, we simplify

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

• junctions by the HIM method has again been demonstrated [48]. Ferromagnetic properties The first demonstration of defect engineering using the HIM was actually for a magnetic device by Franken and co-authors [49]. In this work, ferromagnetic microstrips comprising Pt(4 nm)/Co(0.6 nm)/Pt(2 nm) layers on an

• implementing doses up to 1 × 1017 ions/cm2, stripe patterns were irradiated onto a magnetic thin film structure (this time comprising a ferro- and an antiferromagnetic layer) [53]. The reason for using the higher doses was to investigate the effect of helium implantation and subsequent swelling of the layers

• and the underlying substrate on the magnetic modification obtained. It was found that helium ion bombardment influenced the magnetic anisotropy in both layers of the structure, strongly reducing the saturation magnetization of the layer system. Moreover, the behavior observed correlated with both the

Stability and activity of platinum nanoparticles in the oxygen electroreduction reaction: is size or uniformity of primary importance?

• Kirill O. Paperzh,
• Anastasia A. Alekseenko,
• Vadim A. Volochaev,
• Ilya V. Pankov,
• Olga A. Safronenko and
• Vladimir E. Guterman

Beilstein J. Nanotechnol. 2021, 12, 593–606, doi:10.3762/bjnano.12.49

• friendliness, low operating temperature, and high adaptability of specific characteristics [1][2][3]. The key components of PEMFC membrane–electrode assemblies (MEA) are the proton-exchange polymer membrane and porous electrode layers, in which current-forming reactions of oxygen electroreduction (ORR) and

• best choice [6][7][8]. The most important functional characteristics of the catalytic layers are their activity in the corresponding reactions and stability, which reflects the ability to maintain its activity during operation. These characteristics depend on the PEMFC operating conditions, the

• composition and structure of the catalytic layers, and the catalysts themselves [9]. Platinum–carbon catalysts, whose composition and structure determine their functional characteristics, are the key components of MEA catalytic layers. Of particular importance is the study of the catalyst electrochemical

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• ) properties and bandgap measurements of the deposited layers were also reported. The highest EQE value was obtained for the samples initially etched with a citric acid-based etchant and, in the last preparation step, either passivated with ammonium sulfide aqueous solution or treated with ammonium hydroxide

• ). For the etching of native oxide and suboxide gallium arsenide layers, 50 g of citric acid monohydrate (CA) C6H8O7·H2O (CAS: 5949-29-1) was dissolved into 50 mL of DIW. Since this is an endothermic reaction, the solution temperature initially dropped to approx. 8 °C. Further stirring for several

• passivation layer in the first few ALD cycles. By applying ALD, we were able to create both Al2O3 and AZO layers in a single ALD process conducted at 160 °C. Aluminum oxide was deposited within five cycles of (trimethylaluminum/Al(CH3)3, TMA, CAS:75-24-1) and H2O precursor supply while AZO required 10 multi

Properties of graphene deposited on GaN nanowires: influence of nanowire roughness, self-induced nanogating and defects

• Jakub Kierdaszuk,
• Piotr Kaźmierczak,
• Justyna Grzonka,
• Aleksandra Krajewska,
• Aleksandra Przewłoka,
• Wawrzyniec Kaszub,
• Zbigniew R. Zytkiewicz,
• Marta Sobanska,
• Maria Kamińska,
• Andrzej Wysmołek and
• Aneta Drabińska

Beilstein J. Nanotechnol. 2021, 12, 566–577, doi:10.3762/bjnano.12.47

• and adjacent layers should be studied. It is well established already that graphene grown on silicon carbide is less strained on substrate terraces than on terrace edges, while electron concentration on the edges is lower than that on terraces [4]. This example shows that fluctuations of substrate

• , such as strain induced by mechanical contact between materials or gating of graphene by neighbouring layers, are important for further applications. Furthermore, electron scattering on defects modifies graphene properties in several ways, for example, additional scattering centres reduce carrier

• analysis of graphene G and 2D band parameters provides information about the number of graphene layers, strain, and carrier concentration [11][12][13][14][15]. Furthermore, in defected graphene, D and D’ defect bands are also observed and their intensity values are related to the concentration of defects

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• -BN/Cu(111) substrate. Keywords: decoupling layers; hexagonal boron nitride; local stiffness; Moiré superstructure; work function variation; Introduction Two-dimensional hexagonal boron nitride (h-BN) is among the list of materials that garnered tremendous interest following the exfoliation of mono

• ) [19][20], strain-induced highly corrugated layers for h-BN/Rh(111) [21][22][23], and template layers for molecules with strong local variations of the work function for h-BN/Ir(111) [24] are representative of such morphological diversity. We use low-temperature combined scanning tunnelling (STM) and

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• , especially in SPM under UHV conditions. The ease of its thermal evaporation, the organised structure generally obtained, and the potential of its uses have made C60 a model case for on-surface molecular studies [19][20][21][22][23][24][25][26][27]. Two-dimensional C60 layers have been observed on metals [20

• cluster of Figure 3d. The number of layers ranges from one to at least five. Moreover, the islands present a more rounded shape, compared to TE islands, and no direction favored by the sixfold symmetry is observed. The influence of HV-ESD on the surface itself can also be seen. First, monolayer-deep pits

• single molecules at room temperature hints at a reduced diffusion. A possible explanation is the creation of defects during HV-ESD favoring the trapping of molecules directly upon landing. Conclusion We show the influence of HV-ESD on the surface preparation of molecular layers. This method is known to

On the stability of microwave-fabricated SERS substrates – chemical and morphological considerations

• Limin Wang,
• Aisha Adebola Womiloju,
• Christiane Höppener,
• Ulrich S. Schubert and
• Stephanie Hoeppener

Beilstein J. Nanotechnol. 2021, 12, 541–551, doi:10.3762/bjnano.12.44

• investigation to determine the nanoparticle layers and their Raman activity. For this purpose, the substrates were split in half. Monolayer preparation The 4-ATP monolayers were self-assembled onto cleaned and dried solvent and buffer-treated SERS substrates (see previous section) by immersing the prepared

Surface-enhanced Raman scattering of water in aqueous dispersions of silver nanoparticles

• Paulina Filipczak,
• Krzysztof Hałagan,
• Jacek Ulański and
• Marcin Kozanecki

Beilstein J. Nanotechnol. 2021, 12, 497–506, doi:10.3762/bjnano.12.40

• course, such a strong EF may be registered only if the electromagnetic mechanism of enhancement occurs. By including the subsequent layers of hydration in the calculations, as water molecules participate in the SERS effect (Nsurf), we obtain a lower EF value; however, still in the order of 106. Influence

• hydration layer, but it is also transferred to deeper layers of water up to approx.10 Å (this value is only slightly impacted by the interaction energies). As a result, water molecules around AgNPs have a lower kinetic energy and a longer dwell time that favours structure stabilization. A similar effect has

• molecules. The SERS effect is present only for water molecules that are in direct contact with AgNPs; however, the dynamic properties of water molecules close to the metal surface probably differ from the ones in the bulk up to a couple of hydration layers. This suggests that at least there might be a

Boosting of photocatalytic hydrogen evolution via chlorine doping of polymeric carbon nitride

• Malgorzata Aleksandrzak,
• Michalina Kijaczko,
• Wojciech Kukulka,
• Daria Baranowska,
• Martyna Baca,
• Beata Zielinska and
• Ewa Mijowska

Beilstein J. Nanotechnol. 2021, 12, 473–484, doi:10.3762/bjnano.12.38

• the morphology of the prepared materials, presented in Figure 1, was performed by transmission electron microscopy (TEM). The images of pristine PCN demonstrate the layered structure with a tendency to fold and aggregate. They also show several stacking layers, indicating the planar graphitic-like

• layers). In comparison, the Cl-doped PCN (Figure 2c and Figure 2d) revealed a thickness range from 0.5 to 5 nm (corresponding to 2–14 atomic layers) with the dominating fraction ranging from 2 to 4 nm. The slight enlargement of the lattice parameters can be explained by the unique location of Cl atoms at

• chlorine atoms are located between the carbon nitride layers, as reported by other groups [39][55]. After doping with Cl, the contribution of C–NHx bonds to the XPS signal decreased from 4.23% to 2.49% and that of N3–C bonds from 6.50% to 3.23%, with a simultaneous increase of the N2–C contribution from

A review on nanostructured silver as a basic ingredient in medicine: physicochemical parameters and characterization

• Gabriel M. Misirli,
• Kishore Sridharan and
• Shirley M. P. Abrantes

Beilstein J. Nanotechnol. 2021, 12, 440–461, doi:10.3762/bjnano.12.36

• antimicrobial activities: smaller particles are more efficient to kill bacteria than larger ones. This could be attributed to the higher surface areas that facilitate the attachment to cell membranes [8]. In addition to the different sizes and shapes that AgNPs can have, other metallic layers can be added to

Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

• Zhao Liu,
• Antoine Hinaut,
• Stefan Peeters,
• Sebastian Scherb,
• Ernst Meyer,
• Maria Clelia Righi and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2021, 12, 432–439, doi:10.3762/bjnano.12.35

• hexagonal boron nitride (h-BN), which cannot only be used as a functional insulating monolayer [8][9][10], but can also be stacked with graphene layers [11][12] and has, among other interesting properties, a very stable structural superlubricity [7]. Besides the stacking of different monolayers, the

• intercalation of a third material between a substrate and a 2D layer can be applied to tune the physical properties [13][14][15][16][17]. Schulzendorf et al. reported the electrical decoupling of graphene islands by the intercalation of single layers of KBr between the Cu(111) metal substrate and graphene

• , resulting in quasi free-standing graphene layers [18]. Alkali halide layers are frequently used as decoupling layers in surface science [19][20][21][22]. They are reported to form single- or double-layer islands with a typical cubic structure on single-crystalline transition metal surfaces [23][24