Out-of-plane surface patterning by subsurface processing of polymer substrates with focused ion beams

• Serguei Chiriaev,
• Luciana Tavares,
• Vadzim Adashkevich,
• Arkadiusz J. Goszczak and
• Horst-Günter Rubahn

Beilstein J. Nanotechnol. 2020, 11, 1693–1703, doi:10.3762/bjnano.11.151

• (Figure S1a and Figure S1b, Supporting Information File 1), meaning that this fraction is wasted with regard to defect generation inside the PMMA layer. In contrast, Ne+ and Ga+ ions lose their energy entirely in the PMMA layer; therefore, the total ion energy is utilized for generating the defects 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

• spectrum). An enhancement of radiative interband transitions has been reported for Cu nanoparticles [40]. We thus speculate that surface defects (protrusions) play a role here. This is in agreement with our observation that the intensity of this “defect luminescence” in region I depends on the exact

• ). These peaks shift according to the wavelength of the laser (see Appendix B). Notably, some Raman peaks are superposed in the region of the defect luminescence of the Cu(111) surface (region I), too. 2 Raman modes First, we will discuss the Raman lines. The peaks in the spectrum between 21,000 and 18,600

• primarily observed on rough/nanostructured rather than on flat metal surfaces [45], the SERS effect is expected to be larger for molecules located in proximity to surface defects. Thus, at surface positions with a higher defect density, the Raman intensities are expected to be higher. The relevance of the

PTCDA adsorption on CaF₂ thin films

• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1615–1622, doi:10.3762/bjnano.11.144

• images. These positions are marked by solid white circles and arrows in Figure 3f, while stationary molecules are marked by white dashed circles in both panels. Defects are imaged in STM as black depressions although they are of atomic size [27]. In contrast, the CaF2 surfaces are mostly defect-free. The

• rationalised by nucleation at defects present within the CaF1 interface layer. In contrast, the CaF2/CaF1 layer is mostly defect-free. A statistical analysis revealed a preferred molecular orientation of the long molecular axis along a CaF2 direction, in full agreement with the DFT-calculated optimum

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

• = 10 GΩ. When molecules remain in place, they are imaged as round doughnut-like objects with four positions along the ring, which are imaged brighter (Figure 5a). By manipulating the molecules with the STM tip, we almost never detected a defect in the oxide layer at which the molecules might have been

• pinned. Only if molecules come close to each other or are trapped by a defect does the former dumbbell shape reappear proving that no change of the molecular structure has taken place (Figure 5b). Hence, the round appearance of the molecules is due to a rotational motion much faster than the imaging

• assembly changed between (b) and (c). (a) 1 on 2BL CoO deposited at 200 K and imaged at 80 K. The molecules appear as round features unless close to a neighboring molecule or substrate defect. This indicates that 1 rotates around its central Co ion at time scales that are fast with respect to the STM

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

• , being prochiral, becomes chiral upon surface adsorption [61][77][78], and two stereoisomers can equally be formed on the surface. Each enantiomer segregates into homochiral domains (α and α‘, see Figure 3 and Figure S6, Supporting Information File 1). The lateral extension of the regular, defect-free

One-step synthesis of carbon-supported electrocatalysts

• Sebastian Tigges,
• Nicolas Wöhrl,
• Ivan Radev,
• Ulrich Hagemann,
• Markus Heidelmann,
• Thai Binh Nguyen,
• Stanislav Gorelkov,
• Stephan Schulz and
• Axel Lorke

Beilstein J. Nanotechnol. 2020, 11, 1419–1431, doi:10.3762/bjnano.11.126

• amorphous layer (Ar/H2 ≈59, Figure 4d, right panel). Raman spectroscopy was performed to determine the quality (defect density, defect type, and hybridization) of the deposited Pt/CNW layers. All samples produced at sufficiently high pressures and low carrier gas flow rates exhibit the typical spectrum

• observed for CNWs, with peaks resulting from their graphitic structure and their sharp, exposed edges [30]. At low pressures and high carrier gas flow rates, the intensity of the defect-induced peak D’ increases, as observed in a previous study [17]. The amorphization stage of all samples is 1, which

• percent) determined by XPS. For this, two GCEs were placed close to each other and coated with Pt/CNW in the same process. Afterward, both GCEs were compared to each other via SEM, Raman spectroscopy, and XPS. If the two GCEs were found to be almost identical (in terms of wall density, defect number/type

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

• Jeremiah Croshaw,
• Thomas Dienel,
• Taleana Huff and
• Robert Wolkow

Beilstein J. Nanotechnol. 2020, 11, 1346–1360, doi:10.3762/bjnano.11.119

• literature assignments of several commonly found defects, as well as proposed classifications of previously unreported and unassigned defects. By combining insights from multiple imaging modes, better understanding of their successes and shortcomings in identifying defect structures and origins is achieved

• large, defect free areas [20] – has each surface Si atom in a dimer bonded to one hydrogen atom (Figure 1a,b). The 1 × 1 phase is characterized by the absence of dimer bonds, with each surface Si atom instead saturated by 2 hydrogen atoms, forming silicon dihydrides (H2-Si). The 3 × 1 phase is a

• expected structural geometry (see section Methods), we are able to confirm the atomic structure of several commonly reported defects, as well as to classify previously unknown defects. The latter includes a point defect that can be found decorated with a single H-atom, rendering the otherwise neutral

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

• , we find that irradiating the electrode–channel interface has a deleterious impact on charge transport when contrasted with irradiations confined only to the transistor channel. Keywords: 2D materials; contacts; defect engineering; helium ion microscope; ion beam doping; vacancies; two-dimensional

• defect generation, or full-channel modifications in TMD FETs. A research space exists for exploring the intermediate regime between these two extrema by finely controlling the area over which defects are seeded. For practical devices, it is also important to consider the effect of particle irradiation on

• this paper, we investigate the effect of the defect population on the performance of MoS2 FETs via varying the area of ion irradiation in the FET channel. We also examine the performance of devices upon irradiation of one of the electrical contact interfaces. Experimental Monolayer MoS2 samples were

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

• is that F-doped SnO2 has the lowest defect binding energy. The doping with B and S introduced additional defect energy levels within the forbidden bandgap, which improved the crystal conductivity. The Fermi level shifts up due to the doping with B, F, and S, while the Fermi level of SnO2 doped with C

• that the doping of fluorine and boron elements can provide more surplus electrons to the system. To evaluate the stability of the crystal structure of the doped lattice, it is necessary to calculate the defect binding energy of the lattice. It can be calculated according to Equation 1 [13]: E(AB) is

• the total energy of the doped structure, E(A) and E(B) are the chemical potentials of the atoms, and n is the total number of atoms in the unit cell structure. The total energy and binding energy of the doped structure are shown in Table 3. The defect binding energy values of the doped systems (Table

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

• agrees with the TEM image in Figure 1c, where a homogenous presence of the amorphous component in the shell can be seen. In contrast, the intensity of the c-Si peak (Figure 3e) shows a clear decrease at the lower part of the SiNW. This could originate from a defect, visible as the ring-shaped pattern in

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• was detected, which may be attributed to material degradation arising in WSe2 through the possibility of an increased point defect density at higher temperatures, and/or through oxidative effects. From our preliminary checks on the samples, the Raman spectrum does not recover once the temperature is

• decreased interfacial defect density and built-in strain on sapphire that reduces the electron–phonon interaction in the material [30]. The value of τ obtained in our study is also comparable to what has been reported for τ in 1L CVD grown WSe2 (≈0.76 ps) [30], bilayer CVD grown WSe2 (≈2.4 ps) [29], MoS2

• contributions from each of those scattering sources. Hence, the phonon concentration, defect density, doping concentrations, etc. determine the effective strength of a scattering source and disparities between them cause the differences in the measured lifetimes in 1L, ML and bulk WSe2 which we observed in

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

• a quantum point defect material as well as a photonics material [63]. This choice of material is supported on one hand by the existence of room-temperature single-photon (SP) emission, with the highest brightness and on the other hand by the ability of coherent spin control of some point defects at

• commercial h-BN single crystal. It appears that the SPE was found randomly in the material without treatment. Two families of spectra with ZPL energies at 629 nm and 596 nm were identified. Different charge states of the same defect were attributed to the two emissions, while the small variation of the ZPL

• al. [43]. Here commercial material was annealed in Ar to prevent oxidation and to achieve a higher density of emitters. An SPE PL at 623 nm was observed and tentatively assigned to the antisite point defect VNNB. The SPE is fully polarized along one direction for both excitation and emission, a

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

• -equilibrium Green’s functions. The results show that a single substitutional defect at the interface of armchair graphene and boron nitride nanoribbons can dramatically affect the negative differential resistance behavior depending on its type and location in the structure. Keywords: AGNR/ABNNR

• the conduction band edge [40]. Room temperature (300 K) is considered in all simulations. Results and Discussion Substitutional carbon atoms in boron or nitrogen sublattices (CB and CN) as well as boron or nitrogen atoms on carbon sites (BC and NC) are considered (Figure 2). Each defect could occur

• inside the well or in the contact regions. Since the typical defect concentration for real samples is one defect per ca. 10 Å, one defect of each type is considered at the Gr/hBN heterojunctions [41]. Figure 3 shows the effect of substitutional defects on the energy bandstructure of 19-AGNR and 19-ABNNR

Adsorptive removal of bulky dye molecules from water with mesoporous polyaniline-derived carbon

• Hyung Jun An,
• Jong Min Park,
• Nazmul Abedin Khan and
• Sung Hwa Jhung

Beilstein J. Nanotechnol. 2020, 11, 597–605, doi:10.3762/bjnano.11.47

• composed of both graphitic and defect phases. Therefore, KOH-900 might be useful for adsorption because of defects and the graphitic layers (with π-electrons). Dye adsorption over polyaniline-derived carbon (PDC) Firstly, adsorption of AR1 over PDC and AC was carried out for 6 h. As illustrated in Figure

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• CNTs ruptured upon laser light irradiation [115]. The introduction of graphene oxide (GO) nanosheets with PDDA as multilayers caused the migration and rearrangement of chains compared to PDDA/PAA multilayers [116]. The PDDA/GO multilayers showed improved resistance to damage and maintained a defect

Atomic-resolution imaging of rutile TiO₂(110)-(1 × 2) reconstructed surface by non-contact atomic force microscopy

• Daiki Katsube,
• Shoki Ojima,
• Eiichi Inami and
• Masayuki Abe

Beilstein J. Nanotechnol. 2020, 11, 443–449, doi:10.3762/bjnano.11.35

• -AFM and tunneling current for STM), the surface structure sometimes results in different contrasts in both images. In Figure 3, white squares and circles indicate line defects and protrusions, which are considered to be adsorbates or contamination. A line defect was imaged as a likely vacancy by STM

• defect is the same. Previous studies have reported STM imaging visualizing Ti2O3 rows with a bright contrast [22][24][26][28]. Based on these earlier results, the periodic lines with bright contrast in the NC-AFM image can be identified as Ti2O3 rows. STM and NC-AFM provided different geometry

• information on the line defect. The line defects could be due to be sub-surface defects because of the geometry of the reflected top surface obtained in NC-AFM imaging using the interaction between the tip and the sample surface as a feedback signal. To identify the line defects, it is necessary to combine

Electrochemically derived functionalized graphene for bulk production of hydrogen peroxide

• Munaiah Yeddala,
• Pallavi Thakur,
• Anugraha A and
• Tharangattu N. Narayanan

Beilstein J. Nanotechnol. 2020, 11, 432–442, doi:10.3762/bjnano.11.34

• their long-run alkaline ORR process where the extended stability in electrochemical processes is one of the crucial issues with Pt/C [36]. In all of these doped systems, carbon atoms near to the defect centers are found as catalytically active centers [37]. Recently, an ultra-small amount of selenium

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• particular when the monolayer is defect-rich. MoS2 is known to be naturally high in defects [21][32], in particular S vacancies. It has been predicted that S vacancies in a MoS2 monolayer are most stable when they occur in a row, with a decrease in the vacancy formation energy as the number of vacancies

• slightly shorter than the distances in bulk copper. As for the pristine surface, there is no clear correlation between the geometry and the strength of binding. The presence of a defect did not cause any notable geometry distortions in the monolayer. This is supported by Mo–S distances at the copper

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• “defect” are shown in Figure 6a and the lower inset of Figure 6a, respectively. Whereas, on the nanorod surfaces well-ordered and almost defectless ripples are formed (Figure 6b and Figure 5c,e,f). Similar to the “guiding” effect mentioned above, an ordering effect (at an appropriate fluence) is also

• al. predicting a remarkably defect-free ripple formation on the plane surface by ion bombardment of a binary material should also be noted [10]. In this theory, the composition change of the surface layer by the ion bombardment is discussed and a defect-free ripple formation of an elemental material

• becomes impossible from this point of view. In our experiment we also use binary materials and a defect-free ripple formation is observed, but only for nanorods. However, here, the scenario described in [10] seems unlikely due to a very low energy per atom in the cluster (a few electronvolts) and a

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• ]. It was found that the Kondo resonance is not observed when the Fermi energy is near the Dirac points. The Kondo effect induced by a point defect or a magnetic impurity in graphene has been extensively studied for finite on-site Coulomb interaction within the NRG framework [72][73]. May et al. studied

Size effects of graphene nanoplatelets on the properties of high-density polyethylene nanocomposites: morphological, thermal, electrical, and mechanical characterization

• Tuba Evgin,
• Alpaslan Turgut,
• Georges Hamaoui,
• Zdenko Spitalsky,
• Nicolas Horny,
• Matej Micusik,
• Mihai Chirtoc,
• Mehmet Sarikanat and
• Maria Omastova

Beilstein J. Nanotechnol. 2020, 11, 167–179, doi:10.3762/bjnano.11.14

• graphene or its derivatives have shown that the properties of nanocomposites depend on several factors, such as the polymer type, morphology, intrinsic properties, size and defect level of the filler material, production method, interface between filler and polymer, and others [10][11][12]. Although the

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• compared to ssDNA. The selection of the correct base pairing sequence and order enabled the assembly of DNA with balanced rigidity and flexibility within the nanomaterial systems. The maintenance of an exact stoichiometry and long annealing period were the major criteria to achieve defect-free

Recent progress in perovskite solar cells: the perovskite layer

• Xianfeng Dai,
• Ke Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2020, 11, 51–60, doi:10.3762/bjnano.11.5

• can effectively improve the charge transport efficiency by eliminating the defect and trap density in the perovskite film. The resulting planar PSCs doped with 5 mol % FAAc achieved a PCE of 18.90%, which corresponds to an enhancement of the PCE of over 20% compared to those fabricated by doping with

• because of the unique morphology, which resulted in long carrier lifetime and low defect density. Of course, this precursor solution can be used for slot-die coating to fabricate high-quality PCSs at a high throughput rate. The combination of this special coating solution and the slot-die-coating

Influence of the epitaxial composition on N-face GaN KOH etch kinetics determined by ICP-OES

• Markus Tautz,
• Maren T. Kuchenbrod,
• Joachim Hertkorn,
• Robert Weinberger,
• Martin Welzel,
• Arno Pfitzner and
• David Díaz Díaz

Beilstein J. Nanotechnol. 2020, 11, 41–50, doi:10.3762/bjnano.11.4

• and Al2O3 leads to a high dislocation density, if no strategy for defect reduction is applied. This spans the entire epitaxial layer. The most common strategy to bridge the structural mismatch is the application of AlN and GaN nucleation layers in between the sapphire substrate and bulk GaN [5][6

• ]. Nucleation layers have the second but very important effect of controlling crystal orientation, which is commonly Ga-polar (0001) [7]. Other than nucleation layers, there are several more strategies for defect reduction. These all require the insertion of additional layers or layer transitions into the

Synthesis of amorphous and graphitized porous nitrogen-doped carbon spheres as oxygen reduction reaction catalysts

• Maximilian Wassner,
• Markus Eckardt,
• Andreas Reyer,
• Thomas Diemant,
• Michael S. Elsaesser,
• R. Jürgen Behm and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2020, 11, 1–15, doi:10.3762/bjnano.11.1

• interplanar distance in carbon with a turbostratic structure, and 0.3354 nm for the interplanar distance in a defect-free single crystal of graphite [41][42]. For g-NCS-850 and g-NCS-1000, g values of 0.43 and 0.59 were calculated, respectively. The reflections at 41.2° and 43.6° are associated to the (100

• the number of micropores, and thus of ORR active defect sites. Finally, considering the selectivity for the 4-electron reaction pathway to H2O, which is highly important for technical applications (Figure 8), we find that at potentials below 0.6 V the NCS-1000 catalyst, the best ORR catalyst in this

• directly to one of the N sites, but strongly depends on the amount of defect sites and thus on the microporosity/graphitization of the carbon surface, in combination with a low N-doping. These correlations between structure and ORR activity can be used to further improve the catalytic activity of N-doped