Towards the third dimension in direct electron beam writing of silver

• Katja Höflich,
• Jakub Mateusz Jurczyk,
• Katarzyna Madajska,
• Maximilian Götz,
• Luisa Berger,
• Carlos Guerra-Nuñez,
• Caspar Haverkamp,
• Iwona Szymanska and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 842–849, doi:10.3762/bjnano.9.78

• ]. For the deposition of metals, typically metal-organic precursor compounds are employed [3]. The organic ligands bring the desired metal into the gas phase. Hence, a sufficiently high stability and vapor pressure is usually accompanied by a large amount of carbon in the compound [10]. This carbon is

• appropriate ligands. Even more importantly, the ligands tend to be only weakly bonded and, thus, easily exchange the metal atom [26]. These properties exclude the gas-phase FEBID of silver for conventional gas-injection systems (GIS) that are flanged at the outer chamber walls. Recently, the first gas-phase

• adsorbate-limited deposition regime. Dependent on the actual dwell time of the beam, co-dissociation of non-desorbed ligands as well as of residual carbon hydrates from the vacuum background is expected. Figure 2 displays results for a dwell time series using a 150 pA beam for both precursor compounds. The

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces

• Sven Oras,
• Sergei Vlassov,
• Marta Berholts,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2018, 9, 660–670, doi:10.3762/bjnano.9.61

• surface treatment. One approach is the functionalization of the surfaces with various ligands. For instance, grafting a thin molecular film with hydrophobic tail groups on a surface, formed by self-assembly process, prevents the formation of nano- or microdroplets of water on the treated sample, or

• , but also by the interactions of the NPs and silicon substrate during nanomanipulation in AFM in tapping mode [23]. Despite its inertness [24], Au NPs can be relatively easily functionalized with organic ligands resulting in the formation of stable colloids [23][25]. The possibility of changing the

• ligands chain length, tail group and the packing order (disorder) of the molecular coating makes functionalized NPs an attractive model systems for studying the nature of interactions, and particularly adhesion at the nano and molecular level. The prospect of modifying the chain length of the ligands

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• , and electronic interactions between the stabilizing ligands and nanoparticles [11]. Besides, the creation of a Schottky junction with a noble metal and a semiconductor acts to retard the recombination rate of electrons and holes [12]. LSPR takes place when noble metal NPs are excited by the

Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers

• Yaroslav I. Derikov,
• Georgiy A. Shandryuk,
• Raisa V. Talroze,
• Alexander A. Ezhov and
• Yaroslav V. Kudryavtsev

Beilstein J. Nanotechnol. 2018, 9, 616–627, doi:10.3762/bjnano.9.58

• of pyridine groups with the nanoparticle surface is weaker, thus retaining an opportunity for further changes of the stabilizing ligands. The relative shortcoming of our method is its low net yield, which is below 50% when taking into account both the synthetic and phase transfer stages. Using TEM

Electron interactions with the heteronuclear carbonyl precursor H₂FeRu₃(CO)₁₃ and comparison with HFeCo₃(CO)₁₂: from fundamental gas phase and surface science studies to focused electron beam induced deposition

• Ragesh Kumar T P,
• Paul Weirich,
• Lukas Hrachowina,
• Marc Hanefeld,
• Ragnar Bjornsson,
• Helgi Rafn Hrodmarsson,
• Sven Barth,
• D. Howard Fairbrother,
• Michael Huth and
• Oddur Ingólfsson

Beilstein J. Nanotechnol. 2018, 9, 555–579, doi:10.3762/bjnano.9.53

• electron–molecule interactions rather than the more common thermal fragmentation of precursor species, and various classes of chemical compounds have been considered [4][5] as precursors for FEBID. For instance, metalorganic precursors containing hydrocarbons and chelating ligands can be stable precursors

• and simple in handling, but these benefits come at the expense of incorporation of large amounts of carbon in the deposits by incomplete decomposition or co-deposition of the liberated ligands. Recent developments demonstrate elegant deposit purification techniques to obtain pure, high quality metals

• concluded that in general electron induced dissociation of surface adsorbed precursor molecules proceeds in two steps. Electron induced desorption of ligands associated with the precursor occurs to some extent in the first step (e.g., desorption of one of the PF3 groups in Pt(PF3)4 to form a Pt(PF3)3

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• . Generally, the synthesis of C-dots is a multistep and tedious procedure, which is often expensive. Moreover, a surface passivation with other ligands or additives is frequently needed in order to obtain exacerbated intrinsic fluorescence properties [5][12][13]. Recently, green synthesis methods of C-dots

Electron interaction with copper(II) carboxylate compounds

• Michal Lacko,
• Peter Papp,
• Iwona B. Szymańska,
• Edward Szłyk and
• Štefan Matejčík

Beilstein J. Nanotechnol. 2018, 9, 384–398, doi:10.3762/bjnano.9.38

• both the carboxylate ligands and/or the amine ligands from the complexes. Moreover, the fragmentation of the ligands themselves is visible in the mass spectrum below m/z 140. For the studied complexes the metallated ions containing both ligands, e.g., Cu2(O2CC2F5)(RNH2)+, Cu2(O2CC2F5)3(RNH2)2+ confirm

• -friendly than copper(I) compounds, which are usually air and moisture sensitive, which results in decomposition of the precursor itself. Also, introduction of amine ligands was expected to be advantageous. In fact, the reducing action of ammine ligands was discussed previously with respect to FEBID

• secondary electrons in FEBID acting on much wider range than is the focus of the primary beam leads to broadening of the deposited structure [36]. The importance of the DI and/or DEA processes in FEBID was also discussed by Warneke et al. [37] with the focus on the appropriate choice of the ligands on the

Wafer-scale bioactive substrate patterning by chemical lift-off lithography

• Chong-You Chen,
• Chang-Ming Wang,
• Hsiang-Hua Li,
• Hong-Hseng Chan and
• Wei-Ssu Liao

Beilstein J. Nanotechnol. 2018, 9, 311–320, doi:10.3762/bjnano.9.31

• therefore be fulfilled with different molecules, e.g., ligands, and the substrate is active for biological responses. Comparing to conventional lithographic stamping processes which use mobile inks, this approach solves the problems of molecular lateral diffusion and gas transport obstacles. The fabricated

Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2018, 9, 242–249, doi:10.3762/bjnano.9.26

• sensitizing NiO surfaces for an optimized photon absorption is an on-surface dye synthesis, which has earlier been termed the “surfaces-as-ligands” approach [42]. The first ligand is designed to anchor to the surface through groups such as carboxylic or phosphonic acids and has a metal-binding domain such as

Gas-assisted silver deposition with a focused electron beam

• Luisa Berger,
• Katarzyna Madajska,
• Iwona B. Szymanska,
• Katja Höflich,
• Mikhail N. Polyakov,
• Jakub Jurczyk,
• Carlos Guerra-Nuñez and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 224–232, doi:10.3762/bjnano.9.24

• organic precursors are introduced with a gas injection system (GIS) and physisorb onto the substrate. The electrons induce local precursor dissociation on the surface, which in the ideal case results in a selective and pure metal deposit and volatile organic ligands. However, the organic ligand elements

• interaction into deposited metal atoms and volatile, yet still physisorbed ligands. Due to the high electron flux within the PE beam area, the desorption rate of these volatile ligands is lower than their dissociation rate, resulting in a higher carbon content. Outside the PE beam area, the adsorbates still

• dissociate by electron impact into deposited metal atoms and volatile physisorbed ligands. Yet the desorption rate of the ligands is larger than their further dissociation by the much lower electron flux, preventing co-deposition and leading to purer silver deposits. Due to writing in multiple passes, the

Comparative study of post-growth annealing of Cu(hfac)₂, Co₂(CO)₈ and Me₂Au(acac) metal precursors deposited by FEBID

• Marcos V. Puydinger dos Santos,
• Aleksandra Szkudlarek,
• Artur Rydosz,
• Carlos Guerra-Nuñez,
• Fanny Béron,
• Kleber R. Pirota,
• Stanislav Moshkalev,
• José Alexandre Diniz and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 91–101, doi:10.3762/bjnano.9.11

• capable of defining 3-dimensional metal deposits at nanometre scale for above applications. However, codeposition of organic ligands when using organometallic precursors is a typical problem that limits FEBID of pure metal nanostructures. In this work, we present a comparative study using a post-growth

• (up to 95 atom % relative to carbon) were obtained by means of impact-enhanced desorption of residual organic ligands using a supersonic argon carrier gas jet to deliver the organometallic precursor [45]. Other works suggest the autocatalytic deposition of carbonyls, such as Fe(CO)5 [46][47] and Co2

Electron-driven and thermal chemistry during water-assisted purification of platinum nanomaterials generated by electron beam induced deposition

• Ziyan Warneke,
• Markus Rohdenburg,
• Jonas Warneke,
• Janina Kopyra and
• Petra Swiderek

Beilstein J. Nanotechnol. 2018, 9, 77–90, doi:10.3762/bjnano.9.10

• desired solid material and organic ligands that enhance their volatility. Metal organic precursors are thus used to fabricate metallic deposits. In the ideal case, a pure metal should remain at the surface while the organic ligands decompose into volatile products that are pumped away. However, this is

• usually not the case and material from the ligands tends to be incorporated in the deposit and thus deteriorates its physical properties [1][9][10][11]. Trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe3, Figure 1a) is widely applied as precursor for deposition of Pt because of its very favourable

• with equally small contributions of ethane (C2H6) according to a mass spectrum recorded during the initial stages of electron exposure (Supporting Information File 1, Figure S2). The very small quantity of C2H6, confirms again the previous conclusion [10] that recombination of CH3 ligands dissociating

Response under low-energy electron irradiation of a thin film of a potential copper precursor for focused electron beam induced deposition (FEBID)

• Leo Sala,
• Iwona B. Szymańska,
• Céline Dablemont,
• Anne Lafosse and
• Lionel Amiaud

Beilstein J. Nanotechnol. 2018, 9, 57–65, doi:10.3762/bjnano.9.8

• ligands that are solid and stable under ambient conditions. They are directly deposited on the surface for studying the fragmentation with surface science tools. Results: Infrared spectroscopy and high-resolution electron energy loss spectroscopy (HREELS) are combined to show that the precursor is able to

• spontaneously lose amine ligands under vacuum. This loss can be enhanced by mild heating. The combination of mass spectrometry and low-energy electron irradiation (0–15 eV) shows that full amine ligands can be released upon irradiation, and that fragmentation of the perfluorinated ligands is induced by

• electrons of energy as low as 1.5 eV. Finally, the cross section for this process is estimated from the temporal evolution in the experiments on electron-stimulated desorption (ESD). Conclusion: The release of full ligands under high vacuum and by electron irradiation, and the cross section measured here

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• by plasma synthesis and were not covered with any ligands. Dry NPs were added to LCs at a concentration of 0.25, 0.5 and 1 wt %. The composites were prepared in isotropic phase over one hour by ultrasonication. To estimate ion density (c) and average diffusion coefficient (D) in LC1, LC2 and their

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• ], they are often inefficient in removing the ligands that are currently used to make the precursor molecules volatile [28][29][30]. The decomposition of the precursor is then incomplete, leaving large parts of the ligand structure on the surface. This leads to for instance low metal content and poor

• sufficiently reactive to yield the desired reaction product in a single step, but not so reactive that it dissociates unselectively or has a short shelf life. It has already been determined that electrons cannot remove large ligands. Examples are the cyclopentadienyl ligand in trimethyl(methylcyclopentadienyl

• several questions. How do the ligands determine stability, shelf life and volatility? What is the origin of the short lifetime of ClAuCO in vacuum? Why is MeAuPMe3 volatile, while ClAuPMe3 is not? And can we, based on the results we have, come to a rational design of a Au precursor with the desired

The role of ligands in coinage-metal nanoparticles for electronics

• Ioannis Kanelidis and
• Tobias Kraus

Beilstein J. Nanotechnol. 2017, 8, 2625–2639, doi:10.3762/bjnano.8.263

• . They can be combined with polymers to form conductive composites and have been used as the basis of molecular electronic devices. This review summarizes the multidimensional role of surface ligands that cover their metal cores. Ligands not only passivate crystal facets and determine growth rates and

• shapes; they also affect size and colloidal stability. Particle shapes can be tuned via the ligand choice while ligand length, size, ω-functionalities, and chemical nature influence shelf-life and stability of nanoparticles in dispersions. When particles are deposited, ligands affect the electrical

• properties of the resulting film, the morphology of particle films, and the nature of the interfaces. The effects of the ligands on sintering, cross-linking, and self-assembly of particles in electronic materials are discussed. Keywords: conductivity; inks; layers; ligands; nanoparticles; Introduction

Synthesis of [{AgO₂CCH₂OMe(PPh₃)}_n] and theoretical study of its use in focused electron beam induced deposition

• Jelena Tamuliene,
• Julian Noll,
• Peter Frenzel,
• Tobias Rüffer,
• Alexander Jakob,
• Bernhard Walfort and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 2615–2624, doi:10.3762/bjnano.8.262

• coordination polymer in the solid state as evidenced by single crystal X-ray structure analysis. The coordination geometry at Ag+ is of the [3 + 1] type, whereby the carboxylate anions act as bridging ligands. The formation of PPh3–Ag(I) coordinative bonds results in distorted T-shaped AgPO2 units, which are

• ). Thereby, the carboxylate anions act as µ-bridging ligands to link two adjacent silver(I) ions. Due to the coordination of a PPh3 group to Ag(I), virtually planar AgPO2 coordination units are observed. Planarity is revealed by the calculation of a mean plane. The average deviation from planarity amounts to

Localized growth of carbon nanotubes via lithographic fabrication of metallic deposits

• Fan Tu,
• Martin Drost,
• Imre Szenti,
• Janos Kiss,
• Zoltan Kónya and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2017, 8, 2592–2605, doi:10.3762/bjnano.8.260

• CNT yield [21]. The existence of the corresponding carbon contamination was traced back to deposits from the residual gas in the high-vacuum (HV) environment and the dissociation of the carbon-containing precursor ligands [19]. With our “surface science approach” to FEBIP, that is, working in an ultra

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

• Jusuf M. Khreis,
• João Ameixa,
• Filipe Ferreira da Silva and
• Stephan Denifl

Beilstein J. Nanotechnol. 2017, 8, 2583–2590, doi:10.3762/bjnano.8.258

• further irradiated by a high-energy electron beam. The electron beam decomposes the precursor molecules, leaving the metal on the surface and the organic ligands are pumped away [2][3]. FEBID has shown high potential in growing defined three-dimensional structures close to any geometry and to write on

• uneven surfaces. Although FEBID is a promising technique, improvements are still needed in order to get pure and highly resolved deposits. CVD precursors are normally used as FEBID precursors; however, their performance is limited, leading to co-deposition of ligands and ligand fragments together with

• well as to minimise the adverse or unwanted effects, such as non-pure metal deposition resulting from the co-deposition of ligands. In order to improve the quality of metallic deposits, LEE interactions with organometallic precursors have been studied. Several studies have been reported, e.g., DEA

Direct writing of gold nanostructures with an electron beam: On the way to pure nanostructures by combining optimized deposition with oxygen-plasma treatment

• Domagoj Belić,
• Mostafa M. Shawrav,
• Emmerich Bertagnolli and
• Heinz D. Wanzenboeck

Beilstein J. Nanotechnol. 2017, 8, 2530–2543, doi:10.3762/bjnano.8.253

• is essential for successful binding of ligands, such as thiols [80]. From that point of view, our cleaning procedure presents a valuable approach for experimental realization of structurally sound, precisely patterned nanostructures of a high Au content, with exposed Au surfaces available for

Strategy to discover full-length amyloid-beta peptide ligands using high-efficiency microarray technology

• Clelia Galati,
• Natalia Spinella,
• Lucio Renna,
• Danilo Milardi,
• Francesco Attanasio,
• Michele Francesco Maria Sciacca and
• Corrado Bongiorno

Beilstein J. Nanotechnol. 2017, 8, 2446–2453, doi:10.3762/bjnano.8.243

• immobilize the peptide at the silicon surface. The same behavior can be assumed for shorter peptides. Test of amyloid-beta 1–40 binding by peptide ligands on HES The synthesized pentapeptide KLVFF and a commercial therapeutic heptapeptide, Semax, have been assayed to investigate their ability to bind full

• bind full-length Aβ and to prevent its fibrillation [30]. Semax was chosen for its different behavior (as will be discussed below). The peptides were tested, as amyloid ligands, using the Cy3-labeled Aβ40 conjugate for fluorescence detection. As expected, after the immobilization of the unlabeled

Comparing postdeposition reactions of electrons and radicals with Pt nanostructures created by focused electron beam induced deposition

• Julie A. Spencer,
• Michael Barclay,
• Miranda J. Gallagher,
• Robert Winkler,
• Ilyas Unlu,
• Yung-Chien Wu,
• Harald Plank,
• Lisa McElwee-White and
• D. Howard Fairbrother

Beilstein J. Nanotechnol. 2017, 8, 2410–2424, doi:10.3762/bjnano.8.240

• postdeposition purification strategies capable of removing halogen atoms, despite the presence of halide ligands in many organometallic precursors. Compared to carbon, contaminant halogen atoms in FEBID structures present a different challenge when it comes to purification strategies as they cannot be removed by

• etch substrates or equipment. The use of electrons was motivated in part by previous ultrahigh vacuum (UHV) surface science studies which showed that for 1–2 monolayer (ML) thin films of organometallic precursors with halide ligands, the halogens can be removed [29][31]. The importance of halogen

Electron beam induced deposition of silacyclohexane and dichlorosilacyclohexane: the role of dissociative ionization and dissociative electron attachment in the deposition process

• Ragesh Kumar T P,
• Sangeetha Hari,
• Krishna K Damodaran,
• Oddur Ingólfsson and
• Cornelis W. Hagen

Beilstein J. Nanotechnol. 2017, 8, 2376–2388, doi:10.3762/bjnano.8.237

• eV [50]) has proven to increase molecular fragmentation through DEA considerably [51][52]. Combined with perfluorination of ligands to increase the attachment cross sections at threshold, this could be a viable approach to probe the relevance of DEA by very low energy (0+ eV) SEs produced by the

Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth

• Landon J. Brower,
• Lauren K. Gentry,
• Amanda L. Napier and
• Mary E. Anderson

Beilstein J. Nanotechnol. 2017, 8, 2307–2314, doi:10.3762/bjnano.8.230

• -organic frameworks (MOFs), composed of both metal ions and organic ligands, represent a class of extremely porous, crystalline materials with high surface area. Research has investigated their integration as thin films, namely surface-anchored metal-organic frameworks (surMOFs), into a wide variety of

Dissociative electron attachment to coordination complexes of chromium: chromium(0) hexacarbonyl and benzene-chromium(0) tricarbonyl

• Janina Kopyra,
• Paulina Maciejewska and
• Jelena Maljković

Beilstein J. Nanotechnol. 2017, 8, 2257–2263, doi:10.3762/bjnano.8.225

• ]− channel is visible via two overlapping resonant structures appearing in the energy range below 1.5 eV with a dominant structure peaking at around 0 eV. The peak maxima of the fragments generated by the loss of two or three CO ligands are blue-shifted and the most intense peaks within the ion yield curves

• homoleptic Cr(CO)6. Besides, we have observed the formation of anions due to the loss of C6H6 and one or more CO units. Finally, we found that Cr−, when stripped of all ligands, is generated through a high-energy resonance, peaking at 8 eV. Keywords: benzene-chromium(0) tricarbonyl; chromium(0) hexacarbonyl

• ]), bidentate (e.g., hexafluoroacetylacetone [17]), and mixed ligands (e.g., nitrosyl and carbonyl [9][10], methyl and methylcyclopentadienyl [18], π-allyl, carbonyl, bromide [19]). These studies cover both the fragmentation patterns and kinetics of electron attachment processes. It appears that for carbonyl