Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• electrochemical method, three-dimensional arrayed nanopore structures are machined onto a Mg surface. The structured Mg surface is coated with a thin gold (Au) film, which is used as a surface-enhanced Raman scattering (SERS) substrate. A rhodamine 6G (R6G) probe molecule is used as the detection agent for the

• SERS measurement. Different sizes of arrayed micro/nanostructures are fabricated by different treatment time using the electrochemical process. The topographies of these micro/nanostructures and the thickness of the Au film have an influence on the Raman intensity of the Mg substrate. Furthermore, when

• the thickness of Au film coating is held constant, the Raman intensity on the structured Mg substrates is about five times higher after a treatment time of 1 min when compared with other treatment times. The SERS enhancement factor ranges from 106 to 1.75 × 107 under these experimental conditions

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

• top-down approaches such as thin film deposition and nanopatterning, as well as bottom-up approaches such as chemical synthesis and self-assembly [38]. Gap sizes may range from a few tens of nanometers down to sub-nanometer tunnel junctions, where the classical description of the plasmonic behavior

• focus of an elliptical structure, which is formed by a slit in a gold film. By defining the dimensions of the ellipse, it becomes possible to control the directionality of the emitted light beam. The contributions collected in this Thematic Issue thus highlight current and emerging directions in the

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

• Mehrnoosh Damircheli and
• Babak Eslami

Beilstein J. Nanotechnol. 2020, 11, 1525–1541, doi:10.3762/bjnano.11.135

• experiments done. Firstly, a PS polymer solution (molecular weight of 35000 dissolved in tetrahydrofuran (THF)) was spin-coated at 3500 rpm for 60 s on a cleaned Au substrate. All items were purchased from Sigma-Aldrich. After drying the sample, a portion of the PS thin film was scratched to expose the Au

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

• , an effective electronic decoupling from the metal substrate is achieved. However, on the 1BL film, Co-DPP molecules are sufficiently mobile at 300 K and coalesce to self-assembled molecular islands when cooled to 80 K despite their rather weak intermolecular interaction. In contrast, on the 2BL film

• , due to the rather flat potential landscape, molecular rotation is thermally activated, which effectively prevents self-assembly. The situation is different for 2H-TCNPP, which, due to the additional functional anchoring groups, does not self-assemble on the 1BL film but forms self-assembled compact

• islands on the 2BL film. The findings demonstrate the guiding effect of the cobalt oxide films of different thickness and the effect of functional surface anchoring. Keywords: adsorption energy; molecular rotors; porphyrins; self-assembly; transition metal oxides; Introduction Due to their variability

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

• )/Ag(100) work function after MgO film growth (ΦMgO) by changing the composition at the dielectric–metal interface without changing its surface [16][17][18][19], it has been recently shown that two distinct adsorption regimes exist [20]. On films with a high ΦMgO, all molecules in the ML remain neutral

• work function upon adsorption of the molecules (ΔΦ = Φmol − ΦMgO, where Φmol is the final work function after adsorption of the molecules) is very well described by electrostatics with a simple capacitor model given by where σ is the average charge density in the molecular film, εr is the dielectric

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• nm were synthesized [42]. The chemical vapor deposition method is a technique in which the substrate is exposed to one or more volatile precursors, which react to and/or decompose on the substrate surface to produce the desired thin film deposit. For example, Zhao et al. [44] obtained graphene

Wafer-level integration of self-aligned high aspect ratio silicon 3D structures using the MACE method with Au, Pd, Pt, Cu, and Ir

• Mathias Franz,
• Romy Junghans,
• Paul Schmitt,
• Adriana Szeghalmi and
• Stefan E. Schulz

Beilstein J. Nanotechnol. 2020, 11, 1439–1449, doi:10.3762/bjnano.11.128

• nanometre scale. The target film thickness was 5 nm and was adjusted using the sputtering rate. Figure 1 shows SEM images after the annealing process (Figure 1a–d) and the results of the particle distribution analysis (Figure 1f–j). Figure 1e shows the surface of the Ir sample directly after the ALD process

• particles contribute significantly to surface coverage. The Au film covers 28% of the Si surface, while the Pd film covers more than 40% of the surface. This surface coverage comprises 1522 particles/μm2 at the Au wafers and 845 particles/μm2 at the Pd wafers, respectively. The wafers with copper show a

• broad particle size distribution. The surface is covered by more than 44%, which means 876 particles/μm2. The Pt particles mainly have a diameter below 10 nm with 495 particles/μm2. The total surface coverage did not exceed 1.0%. This result implies that the Pt film was significantly thinner than the

Protruding hydrogen atoms as markers for the molecular orientation of a metallocene

• Linda Laflör,
• Michael Reichling and
• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1432–1438, doi:10.3762/bjnano.11.127

• acid (FDCA) molecules on bulk and thin film CaF2(111) surfaces with non-contact atomic force microscopy (NC-AFM). We use NC-AFM image calculations with the probe particle model to interpret this distinct shape by repulsive interactions between the NC-AFM tip and the top hydrogen atoms of the

• /CaF1/Si(111) thin film samples under ultrahigh vacuum conditions (p < 5 × 10−10 mbar) in two separate systems equipped with appropriate facilities for in situ sample preparation. Bulk CaF2 crystals (Korth Kristalle, Altenholz, Germany) were cleaved in vacuum [24] after degassing the crystal and sample

• details on the thin film growth and properties can be found in [22][26][27][28]. Deposition of 1,1’-ferrocene dicarboxylic acid (purity 98%, Alfa Aesar, Kandel, Germany) on samples held at room temperature was accomplished by sublimation from custom-built Knudsen cells heated to about 390 K. For bulk

Analysis of catalyst surface wetting: the early stage of epitaxial germanium nanowire growth

• Owen C. Ernst,
• Felix Lange,
• David Uebel,
• Thomas Teubner and
• Torsten Boeck

Beilstein J. Nanotechnol. 2020, 11, 1371–1380, doi:10.3762/bjnano.11.121

• beneficial when intentionally used (e.g., to create strongly localized heat sources [7][8]), but it can also be disruptive (e.g., when ultrathin copper layers collapse on titanium nitride, damaging electronic devices [9][10]). However, in thin film applications these phenomena are rarely attributed to the

• values below the abscissa and converges towards zero. This is a major distinction since values above zero leads to the formation of a continuous thin film, whereas values below zero promote the formation of droplets on the surface. Since a gold monolayer has a nominal thickness of 0.32 nm, the maximum

• basic free energy, R is a contribution of the van der Waals energy, Γ is the so-called spreading factor and is the surface area [33]. Since R is a long-range force, it decreases with the square of the film thickness, d2, and increases proportionally to the difference between the Hamaker constants ASF

Impact of fluorination on interface energetics and growth of pentacene on Ag(111)

• Qi Wang,
• Meng-Ting Chen,
• Antoni Franco-Cañellas,
• Bin Shen,
• Thomas Geiger,
• Holger F. Bettinger,
• Frank Schreiber,
• Ingo Salzmann,
• Alexander Gerlach and
• Steffen Duhm

Beilstein J. Nanotechnol. 2020, 11, 1361–1370, doi:10.3762/bjnano.11.120

• PFP this could be ascribed to attractive quadrupole interactions between adjacent PFP molecules [18][56], and this seemed to be the case for partial fluorination as well. The differences in thin film structure were also reflected in the electronic structures, which were distinctively different in

• multilayers on Ag(111). Our results highlight that even for weak organic–metal interaction, the fluorine substitution significantly affects the organic thin film growth beyond the first layer as well as the multilayer electronic structure. Experimental F4PEN was synthesized following an established procedure

• [60] and vacuum-sublimed on clean metal surfaces (prepared by repeated Ar+ ion sputtering and annealing cycles [up to 550 °C]), with deposition rates of about 0.5 Å/min. The film mass thickness was monitored with a quartz crystal microbalance (QCM) near the sample, and a nominal thickness of 4 Å is

Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS₂ field-effect transistors

• Jakub Jadwiszczak,
• Pierce Maguire,
• Conor P. Cullen,
• Georg S. Duesberg and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2020, 11, 1329–1335, doi:10.3762/bjnano.11.117

• achieved by selective ion sputtering in thin film transistors has also been observed in He+-irradiated InGaZnO devices [27]. This irradiation-induced carrier activation depends not only on the fluence of the ion beam, but also on the absolute number of defects that can be introduced. Therefore, the

Structural and electronic properties of SnO₂ doped with non-metal elements

• Jianyuan Yu,
• Yingeng Wang,
• Yan Huang,
• Xiuwen Wang,
• Jing Guo,
• Jingkai Yang and
• Hongli Zhao

Beilstein J. Nanotechnol. 2020, 11, 1321–1328, doi:10.3762/bjnano.11.116

• SnO2; electronic structure; optical properties; Introduction Thin film solar cells are devices that convert solar energy into electrical energy. Transparent conductive films (TCFs) are a thin film material with both conductive capabilities and high transmittance in the visible light range (300–800 nm

• ) [1][2][3]. TCFs serve as the front electrode of thin film solar cells. Up to now, the solar energy conversion efficiency is about 23.3% [4], and it is important to increase the photovoltaic power generation efficiency, as well as the performance of the front electrode. The intrinsic semiconductor

• research works has been done examining different doping elements. Doped tin oxide thin film have been widely used in the fields of thin film solar cell electrodes, electronic display devices, and gas sensors. Also doped SnO2 been used for energy-saving low-emissivity glass coatings due to low resistivity

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

• resist [31]. Chain scission leads to volume loss through the release of gas molecules, and this leads to the shrinkage of exposed PMMA [32], which can be easily quantified using AFM. In a second experiment, we tested the effect on a PMMA thin film exposed to different doses under the focused He ion beam

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

• -STM setup A solution of a porphyrin compound was dissolved in an appropriate solvent (see text) and applied to a freshly cleaved HOPG substrate (10 × 10 mm2, NT-MDT, ZYB) or Au(111) film (10 × 10 mm2 with a thickness of 200 nm evaporated on freshly cleaved muscovite mica) which was mounted into a

Proximity effect in [Nb(1.5 nm)/Fe(x)]₁₀/Nb(50 nm) superconductor/ferromagnet heterostructures

• Yury Khaydukov,
• Sabine Pütter,
• Laura Guasco,
• Roman Morari,
• Gideok Kim,
• Thomas Keller,
• Anatolie Sidorenko and
• Bernhard Keimer

Beilstein J. Nanotechnol. 2020, 11, 1254–1263, doi:10.3762/bjnano.11.109

• are visible in the RHEED pattern of the Nb layer, which indicate island growth and polycrystallinity (Figure 2d). Subsequently, the Fe/Nb multilayers were grown on the 800 °C Nb buffer. The corresponding RHEED patterns exhibit amorphous growth, i.e., blurred screens (not shown). Increasing the Fe film

• thickness from 2 to 4 nm improves the film quality. The Fe layer becomes polycrystalline while the Nb layer remains amorphous. In contrast, for sample s6, which was grown on the 30 °C Nb buffer, both layers reveal polycrystallinity with a certain texture (Figure 2e,f). Finally, the Pt cap is always

• discussions. This work is partially based on experiments performed at the NREX instrument operated by Max-Planck Society at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany. Sample preparation was performed in the thin film laboratory of the Jülich Centre for Neutron Science (JCNS) at Heinz Maier

Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater

• Dinesh Rotake,
• Anand Darji and
• Nitin Kale

Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108

• expanding their deleterious effect on human health and the environment. The proposed technique uses a blend of thin-film and microcantilever (micro-electromechanical systems) technology, which mitigate the disadvantages of the nanoparticle approaches, for the selective detection of Cd(II) with a LOD below

• cantilever sensors. Moreover, the proposed piezoresistive device has capabilities to directly capture the surface stress make this a better option for HMI applications. Microfluidic Platform with Piezosensor In the proposed method, the benefits of three different technologies are combined, namely thin film

Gas sorption porosimetry for the evaluation of hard carbons as anodes for Li- and Na-ion batteries

• Yuko Matsukawa,
• Fabian Linsenmann,
• Maximilian A. Plass,
• George Hasegawa,
• Katsuro Hayashi and
• Tim-Patrick Fellinger

Beilstein J. Nanotechnol. 2020, 11, 1217–1229, doi:10.3762/bjnano.11.106

• (MTI corporation, USA) on an automatic table-top coating machine (Coatema, Germany) using the doctor blade method, resulting in a wet film thickness of 90 µm. The HC loading of the electrodes was 3 ± 0.1 mg cm−2. After drying the films in an oven at 50 °C for 3 h, electrodes with a diameter of 10.95 mm

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

• from Ni(111) due to the beginning adsorption already in the second (or higher) layer(s). Further, the somewhat larger peak widths, as compared to the spectra of DBP on mica [25], might be an inhomogeneous broadening effect caused by a higher degree of rotational disorder in the DBP film on Ni(111

• annealing process does not lead to an increase of the lateral order. However, a highly ordered film was achieved by depositing at a substrate temperature of 170 °C. The LEED image in Figure 3a shows the corresponding diffraction pattern induced by a highly ordered molecular film. For this reason, we labeled

• this sample as highly ordered DBP layer. The DBP layer that was deposited at a substrate temperature of 25 °C, on the other hand, is labeled as less ordered DBP layer. An increase of the crystal quality of the DBP thin film grown at a substrate temperature higher than 90 °C was also reported by Zhou et

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

• similar superstructure with planar C42H28 backbones oriented parallel to the Au(111) surface was reported. In that work a multilayer C42H28 film was deposited at room temperature and subsequently annealed to achieve a monolayer coverage. Different superstructures of C42H28 with twisted and tilted

• indicated by the comparison of the superstructure in Figure 6 with the one obtained for a thicker C42H28 film on graphene-covered SiC(0001) [45]. In the latter work a smaller unit cell was reported with individual C42H28 molecules appearing uniformly in STM images. It is likely that the difference to the

• superstructure depicted in Figure 6 results from an efficiently decoupled molecule residing on top of a molecular film deposited on nearly free graphene on SiC(0001). Similar to observations on Pt(111), C42H28 molecules on graphene appear with two or three lobes in STM images, which are labeled α and β in Figure

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• antenna. This nanoantenna is typically made by chemical etching of a thin Ag or Au wire or by evaporating a Ag or Au thin film on AFM tips. The tip works like an optical antenna when it is brought as close as a few nanometers to the sample surface and when it is illuminated with a tightly focused laser

• light blue and orange lines show the raw spectra, which are composed of a broad photoluminescence continuum emitted from the underlying Au thin film and sharp Raman peaks. For further analysis, these spectral features are fitted using Lorentzian functions for the Raman peaks and a Gaussian function for

• function. The background results from photoluminescence of the Au film. Excitation source: 636.3 nm continuous-wave diode laser. a) Confocal 20 × 20 µm2 image of two intersecting SiNWs on a gold substrate. The yellow square marks the region where a hyperspectral image with16 × 16 spectra was recorded. b

Photothermally active nanoparticles as a promising tool for eliminating bacteria and biofilms

• Mykola Borzenkov,
• Piersandro Pallavicini,
• Angelo Taglietti,
• Laura D’Alfonso,
• Maddalena Collini and
• Giuseppe Chirico

Beilstein J. Nanotechnol. 2020, 11, 1134–1146, doi:10.3762/bjnano.11.98

• efficiency, while preserving the original photothermal properties of these nanoparticles [33][38]. This strategy may also offer a powerful alternative for the preparation of new antibacterial bulk materials and objects, and for film-coating the surface of preformed objects in any shape. The laser-induced

• nanohole arrays with reduced graphene oxide nanosheets in a unique and flexible polyimide film for laser-gated pathogen inactivation. For the in vivo experiments, the patch was irradiated for 5 min with an LED array (940 nm, 10 W) and the patch surface temperature increased to 52 °C. These tests indicated

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

•  1b,c). Temperature measurements are performed using the temperature-dependent fluorescence of sulforhodamine B (Radiant dyes Chemie), which is calibrated in an independent measurement (accuracy ±2 K). Since the sapphire glass with a high thermal conductivity helps cooling the thin sample film, the

Plant growth regulation by seed coating with films of alginate and auxin-intercalated layered double hydroxides

• Vander A. de Castro,
• Valber G. O. Duarte,
• Danúbia A. C. Nobre,
• Geraldo H. Silva,
• Vera R. L. Constantino,
• Frederico G. Pinto,
• Willian R. Macedo and
• Jairo Tronto

Beilstein J. Nanotechnol. 2020, 11, 1082–1091, doi:10.3762/bjnano.11.93

• analytical techniques, including powder X-ray diffraction, thermogravimetric analysis coupled to differential scanning calorimetry and mass spectrometry, specific surface area measurement, and scanning electron microscopy. Bioassays were performed with the seeds coated with the composite film to assess the

• germination rate and germination speed index of the seeds, as well as biometric analyses including measurements of root area, root fresh matter, and shoot length of the plants. The bioassay performed in soil pots showed that the alginate film containing ZnAl-NAA-LDH yields an enhancement regarding root area

• action of auxin in plants, we examined in this work the intercalation of NAA in inorganic layers of LDHs, with the subsequent production of a composite film with alginate [16][17] to provide physical and chemical protection for the intercalated auxin substances. It is expected that the application of

Vibration analysis and pull-in instability behavior in a multiwalled piezoelectric nanosensor with fluid flow conveyance

• Sayyid H. Hashemi Kachapi

Beilstein J. Nanotechnol. 2020, 11, 1072–1081, doi:10.3762/bjnano.11.92

• . investigated the effect of nonzero initial conditions, the nonlinear coefficient of squeeze film air damping, and the van der Waals effect on the stability of torsional nanomirrors for the obtained dynamic pull-in instability voltage using the size effect [14]. Fakhrabadi et al. utilized the modified couple

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• costs [3][4][5][6][7][8][9][10]. It has been shown that Sb2Se3 has many applications in photovoltaic devices and thermoelectric systems where it can be used as a thin film [11], in thermovoltaic and switch devices [12], in optical data storage [13] and in optoelectronics as a 2D anisotropic material [14