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

• the introduction of lattice defects has been demonstrated in a variety of nanoengineering applications. The generation of vacancies, preferential sputtering of one atomic species over another, and the introduction of increasing amounts of disorder leading to eventual amorphization of a crystalline

• material are all dials to turn. The properties engineered span electronic, magnetic, optical, chemical, and thermal properties. In the case of 2D and thin-film materials supported on a substrate, defects induced by backscattered ions and sputtered atoms also need to be considered. A recent computational

• . investigated the nature of the ion-induced defects further, and determined that after irradiation, the ion-induced vacancies become saturated with oxygen [20]. The authors of the latter thus proposed that the mechanism behind the irradiation-induced insulating behavior involved oxygen groups acting as charge

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

• ]; differences in the principles of calculation, which serve as the basis for the corresponding research methods [41]; a possible contribution of NP structural defects to the broadening of the X-ray diffraction pattern maxima [42], and problems related to the recognition of ultra-small particles in TEM

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

• before to be resulting from complexes of Al3+ ions and VZn [40]. These complexes resulted from the substitution of Zn2+ ions with Al3+ ions. The region above 450 nm is ascribed as the reflection of point defects present in the ZnO structure [41]. One can observe a broad band typically present in undoped

• ZnO [42] with intensity varying depending on the crystallization conditions. Additionally, local maxima may be discriminating the presumable presence of specific defects: 445, 458 (VZn), 480 (Zni+), 516 (VZn−, ZnO), and 560 nm (observed only in the B2 sample, possibly due to AsOx luminescence [43

• ]). The intensities of the defect bands in relation to each other and to the NBE band are associated with the route of AZO growth. The point defects usually observed in ZnO are: oxygen vacancy VO, zinc vacancy VZn, interstitial oxygen Oi, interstitial zinc Zni, and oxygen antisite OZn [44][45]. The

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

• nanowires impact graphene properties such as roughness, strain, and carrier concentration as well as density and type of induced defects. Tracing the manifestation of those interactions is important for the application of novel heterostructures. A detailed analysis of Raman spectra of graphene deposited on

• contact with graphene. The lowest concentration of defects is observed for graphene deposited on nanowires with the lowest density. The contact between graphene and densely arranged nanowires leads to a large density of vacancies. On the other hand, grain boundaries are the main type of defects in

• graphene on rarely distributed nanowires. Our results also show modification of graphene carrier concentration and strain by different types of defects present in graphene. Therefore, the nanowire substrate is promising not only for strain and carrier concentration engineering but also for defect

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

• expected at low bias voltages making it transparent to STM, as seen in Figure 2b,d. At this bias, only Friedel oscillations due to the scattering of the Cu(111) surface-state electrons on defects and adsorbates are observed. Contrarily, as Figure 2a reveals, at higher bias, the STM topography corresponds

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

• nm. An important difference is that many of the C60 islands are observed in the middle of the terraces, that is, far away from step edges. This phenomenon, not observed for TE, suggests a difference in the nucleation during island formation. It could be explained by the presence of defects on the

• surface. These defects, induced by the HV-ESD method itself, could allow for the trapping of C60 molecules and island nucleation far away from step edges. The separation distance between islands can also be small, as indicated by the white arrow and observed in several place in Figure 2b. Another

• of the herringbone reconstruction, a favorable trapping site [38]. The height of the dots is too small to be C60 molecules and the dots are therefore attributed to solvent. Nevertheless, such defects can influence the nucleation and the size of C60 islands. The presence of the solvent on the surface

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

• Reimer Karstens,
• Thomas Chassé and
• Heiko Peisert

Beilstein J. Nanotechnol. 2021, 12, 485–496, doi:10.3762/bjnano.12.39

• part of the TMPcFx molecules in the first monolayer might be related to local interactions with Ti and/or Sr atoms. Also, interactions between the macrocycle of the TMPc and the rutile TiO2 surfaces seem to depend critically on the number of surface defects [50]. Thus, the absence of interface

Spontaneous shape transition of Mn_xGe_1−x islands to long nanowires

• S. Javad Rezvani,
• Luc Favre,
• Gabriele Giuli,
• Yiming Wubulikasimu,
• Isabelle Berbezier,
• Augusto Marcelli,
• Luca Boarino and
• Nicola Pinto

Beilstein J. Nanotechnol. 2021, 12, 366–374, doi:10.3762/bjnano.12.30

• relieve the epitaxial strain between the 2D Mn layer and the substrate occurs (significantly increasing the critical thickness for crystallographic defects nucleation). Second, there is the spontaneous elongation of 3D islands also induced by strain relaxation, which is the driving force leading to the

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• graphene oxide, rGO) chemically or thermally. Through the partial removal of oxygen groups, the conductivity can be restored. Additionally, defects and vacancies are created [26]. Because of the ultra-high surface area per atom and the high electron transport along the graphene plane, rGO has a rapid and

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• including, but not limited to, the direct writing of defects to act as nuclei for epitaxial growth [25], the fabrication of two-dimensional phononic crystals [26], the magnetic patterning of suspended Co/Pt multilayers, the fabrication of two-dimensional mechanical resonators based on single-layer graphene

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

• analysis of single FePc molecules trapped at surface defects indicates that the molecules stay intact upon adsorption and can be manipulated away from surface defects onto a perfectly hydrogenated surface. This allows for their isolation from the germanium surface. Keywords: hydrogenated semiconductor

• nanoislands. Our STM data indicate that FePc molecules stay intact upon adsorption. While single molecules are trapped at surface defects and could be manipulated with the STM tip away from the defects onto the perfectly hydrogenated Ge(001):H surface, the major fraction of the molecules could be found within

• defects could be identified within the surface [61][62][63][64][65]. These are mainly single or double hydrogen vacancies. This means that within a Ge dimer either one hydrogen atom is missing, this is called a single dangling bond (DB), or the dimer lacks both hydrogen atoms and the so-called dangling

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

• combination of these two species forms the characteristic stripe pattern of the z’-TiOx phase. Inside the trenches between the stripes, several holes in the film can be found, which are probably caused by the stress release during the film growth. These defects permit a direct contact with the underlying

• substrate and, thus, they should be special attraction points for adsorbates. As shown in Figure 1c and Figure 1d, it is very probable that W3O9 clusters prefer to adsorb these defects inside the trenches of the z’-TiOx phase. The result is a 1D alignment of the clusters along the direction of the stripes

• interaction with the substrate. The exclusive positioning of the W3O9 clusters on the point defects inside the trenches leads us to the conclusion that the preferred interaction with the metallic substrate below the oxide film compensates any charge injection or removal induced by the STM tip. For that

ZnO and MXenes as electrode materials for supercapacitor devices

• Ameen Uddin Ammar,
• Ipek Deniz Yildirim,
• Feray Bakan and
• Emre Erdem

Beilstein J. Nanotechnol. 2021, 12, 49–57, doi:10.3762/bjnano.12.4

• materials provide a fundamental understanding regarding the manner in which 2D structures are impacted by defects compared to bulk. Such an approach would therefore serve the scientific community with the material design tools needed to fabricate the next generation of supercapacitor devices. Keywords: 2D

• 2D structures are impacted by defects compared to the bulk. Such an approach would therefore serve the scientific community with the materials design tools needed to fabricate the next generation of supercapacitor devices. It must be borne in mind that the way in which carrier transport is enhanced

• in semiconductors is fundamentally the same, regardless of composition. Defects generate bandgap states that either generate electrons in the conduction band or holes in the valence band. Therefore, we believe that the discussion, based on experimental results, of the magnitude of this effect for 2D

Atomic layer deposited films of Al₂O₃ on fluorine-doped tin oxide electrodes: stability and barrier properties

• Hana Krýsová,
• Michael Neumann-Spallart,
• Hana Tarábková,
• Pavel Janda,
• Ladislav Kavan and
• Josef Krýsa

Beilstein J. Nanotechnol. 2021, 12, 24–34, doi:10.3762/bjnano.12.2

• , or to the perovskite (depending on the device type). This parasitic effect occurs through defects, such as pinholes and cracks in the blocking layer. Their presence is identified by the occurrence of anodic currents assigned to the oxidation of [Fe(CN)6]4− at FTO areas exposed by these defect sites

• that of pure FTO is higher than three. This means that there are B-type defects in the barrier film. These defects cause not only the delamination of the Al2O3 film from the FTO substrate, but also a slowdown of the charge-transfer kinetics (accompanied by a strong increase in ΔEpp). The Table 1 shows

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

Towards 3D self-assembled rolled multiwall carbon nanotube structures by spontaneous peel off

• Jonathan Quinson

Beilstein J. Nanotechnol. 2020, 11, 1865–1872, doi:10.3762/bjnano.11.168

• /N2/C3 structure is shown in Figure 2. The D peak refers to a defect in the MWCNT structure. An intense D peak (relative to the G peak intensity) correlates to higher defects, for instance, induced by nitrogen doping. The G and 2D peaks are related to the graphitization of MWCNTs. An intense G peak

Nanocasting synthesis of BiFeO₃ nanoparticles with enhanced visible-light photocatalytic activity

• Thomas Cadenbach,
• Maria J. Benitez,
• A. Lucia Morales,
• Cesar Costa Vera,
• Luis Lascano,
• Francisco Quiroz,
• Alexis Debut and
• Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

• catalytic performance in terms of overall degradation efficiency of the 5.5 nm particles is significantly superior compared to those of similarly sized particles reported. It also much improved when compared with samples free of surface defects synthesized by a previously reported co-precipitation method

• lead to a decrease in photocatalytic activity due to crystal defects and local distortions altering the skin layer of the BiFeO3 photocatalysts [28][53][56]. From this results we conclude that the nanocasting method for the synthesis of BiFeO3 does not only produce pure-phase, uniform BiFeO3 with a

• very narrow particle size distribution. The results also suggest that the nanoparticles are characterized by a low concentration of surface defects and a low level of local strain, which is ideal for surface-based applications such as photocatalysis. This is confirmed by the reaction kinetics of the

Molecular dynamics modeling of the influence forming process parameters on the structure and morphology of a superconducting spin valve

• Alexander Vakhrushev,
• Aleksey Fedotov,
• Vladimir Boian,
• Roman Morari and
• Anatolie Sidorenko

Beilstein J. Nanotechnol. 2020, 11, 1776–1788, doi:10.3762/bjnano.11.160

• cobalt with an increase in the substrate temperature will decrease the transparency parameter TF and worsen the functional parameters of the layered S/F heterostructure. The implementation of optimal technological processes is required to minimize these defects and imperfections of layered nanosystems

Mapping of integrated PIN diodes with a 3D architecture by scanning microwave impedance microscopy and dynamic spectroscopy

• Rosine Coq Germanicus,
• Peter De Wolf,
• Florent Lallemand,
• Catherine Bunel,
• Serge Bardy,
• Hugues Murray and
• Ulrike Lüders

Beilstein J. Nanotechnol. 2020, 11, 1764–1775, doi:10.3762/bjnano.11.159

• the measurements of the electrical interactions of a biased tip–sample nanoscale system [1][2]. Scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM) [3][4][5] are modes widely used for the detection of charge carriers, carrier types, and density of defects. These

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

• wrinkle-like micropatterns [23][24]. In this work, we have employed thin films of a Pt60Pd40 alloy and of pristine Au. The primary reason for this choice was the difference in their microstructures, specifically in the availability of structural defects capable of providing the release of gases from

• (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

• the optical excitation can occur. The different FL lines can be ascribed to different environments of the adsorption sites, namely molecules adsorbed at surface defects, in large ordered domains, and located in the second layer. Keywords: decoupling; fluorescence; hexagonal boron nitride; 3,4,9,10

• 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

• additional enhancement [46]. According to the electromagnetic mechanism, on a rough surface, surface plasmon polaritons (SPPs) can also be excited by the incident light. The surface plasmons are located in the vicinity of surface defects, such as protrusions. The field enhancement at these defects leads to

PTCDA adsorption on CaF₂ thin films

• Philipp Rahe

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

• (111) surface with deposition on thicker CaF2/CaF1/Si(111) films. The identification of mostly single molecules on the CaF1/Si(111) interface layer is explained by the presence of atomic-size defects within this layer. Geometry-optimisation calculations using density functional theory reveal a geometry

• ) reconstruction. After PTCDA deposition, individual double-lobe features are apparent in STM at negative sample bias on the CaF1/Si(111) areas (see also Figure 1b), in addition to the dark spots that were identified before as single atomic-size defects within the CaF1 interface layer [27]. Each of these double

• , coupling to defects within the CaF1 layer, or charge transfer into the LUMO. Imaging at a positive sample bias of +1.5 V was performed in constant-height mode as the reduced sample conductivity at positive bias impeded operation in constant-current mode. Still, conductivity through PTCDA molecules is also

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

• deposited on the surface. The parameters and duration of the PEO process should be carefully determined, as intensive energy input and longer treatment duration may create excessive surface roughness or even introduce unexpected defects on the surface. Thus, a set of moderate parameters was applied in this

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

• , it is also an anti-ferromagnet due to electron correlation effects and it shows catalytic activity [14][15][16][17]. As a thin film grown on Ir(100), the oxide is of extremely high quality [18][19][20] avoiding the complexity that arises from atomic-scale defects in bulk materials [5][6][7][8]. The

• diffusive motion of the molecules since the directional intermolecular bond always “swings open”. Increasing the annealing temperature does not help to form supramolecular structures at low coverage. At 300 K, all molecules will attach to defects or move to 1BL CoO areas present in the film. In contrast, 2

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

• surface has to be determined: However, this equation is only valid for equilibrium states on ideal surfaces. Defects on the substrate can lead to hysteresis effects that change the contact wetting angle [38]. Other surface effects, such as coarsening, ageing, or ripening can additionally lead to