Chemistry for electron-induced nanofabrication

• Petra Swiderek,
• Hubertus Marbach and
• Cornelis W. Hagen

Beilstein J. Nanotechnol. 2018, 9, 1317–1320, doi:10.3762/bjnano.9.124

• simultaneous injection of a reactive gas [25]. Also, it is demonstrated that the metal content of a Au deposit can be significantly increased by continued electron irradiation and a final boost of oxygen plasma cleaning [26] and that the purity of deposits from different metals is enhanced by thermal treatment

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• (such as annealing, post-deposition annealing in O2, exposure to atomic hydrogen, post-deposition electron irradiation) were proposed as viable techniques [7][8], but these approaches are not completely free from reproducibility issues. Therefore, to improve the metal content and to address the nature

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

• are largely unaffected by either further electron irradiation or annealing to room temperature, with a predicted metal content similar to what is observed in FEBID. Furthermore, gas phase experiments indicate formation of Fe(CO)4 from H2FeRu3(CO)13 upon low energy electron interaction. This fragment

• ), reflection-absorption IR spectroscopy (RAIRS), and/or high-resolution electron energy loss spectroscopy (HREELS), while mass spectrometry has been used to identify gas phase species generated as a result of electron irradiation. As such the surface science experiments represent an increased level of

• conditions (Pbase < 4 × 10−9 mbar). Ultra-thin (<2–3 nm) H2FeRu3(CO)13 films were deposited onto a cooled, sputter-cleaned Au substrate before being exposed to 500 eV incident electrons generated by a commercial flood gun. The effect of electron irradiation on the adsorbed H2FeRu3(CO)13 molecules 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

• )/synthesized = 242−244 °C/247 °C). Previous measurements indicated thermal stability of the precursor in the gas phase up to 220 °C [18]. Upon electron irradiation of the pristine solid precursor compound, a strong increase in silver content from 9 to >40 atom % was observed. Thermal stability and electron

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

• highly contaminated by carbon originating from the precursor used in the process. Recently, it was shown that platinum nanostructures produced by FEBID can be efficiently purified by electron irradiation in the presence of water. If such processes can be transferred to FEBID deposits produced from other

• . Therefore, different purification processes have been devised to turn the material into high-purity Pt [9][11][14][15][16]. In particular, post-deposition treatment with O2 at elevated temperature [9], the simultaneous exposure of the deposit to O2 and further electron irradiation [14][15][16], as well as

• at 150 K and 210 K, respectively. We note that at temperatures between 250 K and 350 K slightly increased intensities of the methane signals were detected. These amounts are, however, negligible in comparison to reaction products formed under electron irradiation, as shown in the following. Electron

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

• 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

• should be not only in the gas phase, but also it needs to be deposited on the surface where the electron beam is focused. The main motivation of the present study is to get insights on the response of this precursor under FEBID conditions, i.e., under electron irradiation in vacuum. We separate here the

Amplified cross-linking efficiency of self-assembled monolayers through targeted dissociative electron attachment for the production of carbon nanomembranes

• Sascha Koch,
• Christopher D. Kaiser,
• Paul Penner,
• Michael Barclay,
• Lena Frommeyer,
• Daniel Emmrich,
• Patrick Stohmann,
• Tarek Abu-Husein,
• Andreas Terfort,
• D. Howard Fairbrother,
• Oddur Ingólfsson and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2017, 8, 2562–2571, doi:10.3762/bjnano.8.256

• approximately 1:0.7:0.6. Inspired by these results, self-assembled monolayers (SAMs) of the respective biphenyl-4-thiols, 2-Cl-BPT, 2-Br-BPT, 2-I-BPT as well as BPT, were grown on a Au(111) substrate and exposed to 50 eV electrons. The effect of electron irradiation was investigated by X-ray photoelectron

• chlorine signal is fitted by its specific doublet Cl 2p1/2 + Cl 2p3/2, while for bromine, only the Br 3p3/2 is used to quantify the signal of interest. It is clear from Figure 2 that the XPS intensity of the respective halogens decreases for all three molecules upon electron irradiation. For 2-I-BPT (right

• curve). All three curves show a strong exponential decrease with increasing electron irradiation. This is consistent with the expected cleaving of the halogen–carbon bonds and a subsequent detachment of the halogen atoms. This decrease in the normalized intensity, Ihalog/Ihalog0, is similar for Br 3p

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

• purity [48]. For cobalt, a combination of heat, H2 exposure and electron irradiation improved the metal content in the deposits [49]. Similarly, in the case of platinum, several purification approaches have been studied, including laser assisted purification [50][51], a sequential EBID process and

• additional postdeposition electron irradiation in the presence of H2O or O2 [52][53][54][55][56]. The mechanisms behind these processes point to fundamental differences between molecular oxygen and water as oxidative species [57]. Similar purification methods have also been investigated for gold, but

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

• resistivity only six times greater than pure Pt metal. In a study by Lewis et al. [21], FEBID nanostructures created from MeCpPtMe3 were subsequently purified by electron irradiation in the presence of oxygen and examined by cross-sectional SEM, which revealed that purification occurred in a top-down fashion

• min nA−1μm−2. The results were consistent with extremely fast inward diffusion of the water molecules through the carbon matrix, after which the incorporated water was dissociated by electron irradiation to produce reactive oxygen species. Cross-sectional TEM data revealed that purification does not

• desorption initiated by electron irradiation in FEBID is also supported by the observation that FEBID nanostructures created from WF6, WCl6 and SiH2Cl2 contain (W/Si):halogen ratios far greater than those of the precursor molecules [32][33]. Indeed, in the case of SiH2Cl2, electron beam irradiation of an

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

• amounts of carbon [4][21]. However, as shown in this paper, for the case of a chromium complex carrying a benzene ligand, such large organic entities may be more easy to remove by electron irradiation than generally anticipated. Chromium complexes are of interest because they are used for various

Suppression of low-energy dissociative electron attachment in Fe(CO)₅ upon clustering

• Jozef Lengyel,
• Peter Papp,
• Štefan Matejčík,
• Jaroslav Kočišek,
• Michal Fárník and
• Juraj Fedor

Beilstein J. Nanotechnol. 2017, 8, 2200–2207, doi:10.3762/bjnano.8.219

• polarizable nature of argon, may be so effective that the cross section of the whole band at energies <2 eV is below the detection limit of the CLUB setup. Similar shielding has been postulated in electron-irradiation CH3I condensed on rare gas films [10][11]. In the vast majority of molecules, the vicinity

• the ”slightly unbound” analogue. Nonetheless, the effect of shielding due to polarizability of the surroundings (either surface or clusters) can be expected to be the same. Massey et al. [20] have recently probed the anion desorption from iron pentacarbonyl thin films condensed on xenon upon electron

• irradiation and reported no desorption signals below 5 eV. The authors attributed this primarily to low desorption probability of fragments produced at low electron energies. In view of the present results, the shielding of the long-range interactions by the bulk surface could be responsible for such an

Modelling focused electron beam induced deposition beyond Langmuir adsorption

• Dédalo Sanz-Hernández and
• Amalio Fernández-Pacheco

Beilstein J. Nanotechnol. 2017, 8, 2151–2161, doi:10.3762/bjnano.8.214

• under electron irradiation [39]. This demands for new frameworks which describe FEBID processes more generally and under a wide range of experimental conditions [40]. Here, we generalize the FEBID continuum model, going beyond Langmuir adsorption, that is, allowing the system to form adsorbate coverages

• included. Second, the detailed adsorption state, coverage and order, as well as the electron irradiation, may significantly alter the values for attempt frequency, adsorption energy, and dissociation cross section, as well as the order of desorption [44][45][46][47][48]. These factors are not considered

• physi-adsorption when E1 ≠ E2. This is essential when working on surfaces which may be chemically activated by electron irradiation [48]. Chemisorbed adsorbates are common, for instance, when using FEBID precursors leading to highly metallic deposits, such as Co2(CO)8, Co(CO)3NO and Fe(CO)5, where

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

• Carlos Angulo Barrios and
• Víctor Canalejas-Tejero

Beilstein J. Nanotechnol. 2017, 8, 1231–1237, doi:10.3762/bjnano.8.124

• influence of the electron irradiation in the regions adjacent to those directly exposed by the electron beam) [11]. The Si substrate of the actual device is omitted in the model because the 100 nm thick Al film on which the nanocages rest is optically opaque. It is also assumed that oxidation of the Al cage

Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers

• Kai Rückriem,
• Sarah Grotheer,
• Henning Vieker,
• Paul Penner,
• André Beyer,
• Armin Gölzhäuser and
• Petra Swiderek

Beilstein J. Nanotechnol. 2016, 7, 852–861, doi:10.3762/bjnano.7.77

• smaller structures, namely, when electron exposure leads to formation of nanoparticles (NPs) in the irradiated surface area. Hierarchical surface patterns are thus accessible. In fact, the formation of metal NPs under electron irradiation has been observed in diverse precursor materials such as solid [11

• rather homogeneous distribution of monodisperse NPs has been achieved by electron irradiation and subsequent washing of well-organized silver(I) dodecanethiolate layers [19]. Also, self-assembled layers can be prepared by simple wet-chemical dipping processes [21][22] or high-throughput spray

• surface-grown layers of copper(II) oxalate are, in fact, transformed to pure Cu NPs by low-energy electron irradiation at room temperature while the oxalate ions are completely removed through the same electron-induced process that yields the NPs. This makes post-irradiation steps obsolete, which would

Electrospray deposition of organic molecules on bulk insulator surfaces

• Antoine Hinaut,
• Rémy Pawlak,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2015, 6, 1927–1934, doi:10.3762/bjnano.6.195

• step-edge. Pits similar to what can be obtained after electron irradiation of the surface are visible [47]. Sample charging was not observed and bias remained in the ±1 V range. Small objects with sizes compatible with single molecules decorate both terraces. Due to the shorter deposition time, 2 min

The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

• Rachel M. Thorman,
• Ragesh Kumar T. P.,
• D. Howard Fairbrother and
• Oddur Ingólfsson

Beilstein J. Nanotechnol. 2015, 6, 1904–1926, doi:10.3762/bjnano.6.194

• studies on adsorbed precursor molecules can provide information on surface speciation and identify species desorbing from a substrate during electron irradiation under conditions more representative of FEBID. Comparing gas phase and surface science studies allows for insight into the primary deposition

• with XPS and MS, and with RAIRS, respectively, as well as commercial flood guns for use as electron sources. The MeCpPtMe3 precursor was physisorbed onto gold substrates at about 180 K and irradiated with electrons with 500 eV impact energy. During electron irradiation, a MS with a 70 eV electron

• irradiation. The only visible species during electron irradiation are at m/z 15, 16, and 2. These are assigned to CH3+, CH4+, and H2+, with the former two appearing at the ratio observed in electron impact ionization of gas phase methane (CH4). The initial loss of a methyl radical is likely to result from a

Atomic scale interface design and characterisation

• Carla Bittencourt,
• Chris Ewels and
• Arkady V. Krasheninnikov

Beilstein J. Nanotechnol. 2015, 6, 1708–1711, doi:10.3762/bjnano.6.174

• refined, for example new understandings of diffusion processes during growth and oxidation allow for the engineering of hollow nanostructures using the Kirkendall effect [10], the filling of carbon nanotubes and nanofibers to tune their properties [11], or the use of electron irradiation to produce carbon

• transmission electron microscopes (TEM), which brings both increased spatial resolution and energy resolution allowing imaging at low voltage, crucial for nanomaterials which are sensitive to electron irradiation. Currently, the atomic structure of different nanomaterials can be revealed with a resolution of

• density-functional theory (DFT) approaches. In addition, using DFT-based molecular dynamics, the manipulation of nanostructures by SPM tools and the changes made to the system by the characterization tools, e.g., the production of defects under electron irradiation and their evolution over time, can be

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• . Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces

• subsequent reconstruction of large even-number vacancies takes place, as discussed in detail in [43]. One example is shown in Figure 4a,b. When carbon atoms in CNTs are displaced by electron irradiation, single vacancies (SV), divacancies (DV), and even tetravacancies can be created; a schematic illustration

Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• limit the majority of our discussion to diffusion-less models. Initial adsorbate coverage FEBIP models require specification of the initial concentration of surface-adsorbed precursor molecules , i.e., the steady-state concentration of adsorbates in the absence of electron irradiation. can be found by

• model, i.e., the time at which the gas pressure is changed from 0 to Pa. A typical time-evolution of Na in the absence of electron irradiation is shown in Figure 3. As t → ∞, the surface coverage reaches a steady-state equilibrium value, , which is the initial value that is input into FEBIP models (in

• through electron induced dissociation (−∂Nα/∂t). In Equation 12, t = 0 represents the time at which electron irradiation is activated in the model, and the initial adsorbate concentration is given by Equation 7. Most models of FEBIP assume that the adsorbate dissociation flux, ∂Nα/∂t, is proportional to

Formation of pure Cu nanocrystals upon post-growth annealing of Cu–C material obtained from focused electron beam induced deposition: comparison of different methods

• Aleksandra Szkudlarek,
• Alfredo Rodrigues Vaz,
• Yucheng Zhang,
• Andrzej Rudkowski,
• Czesław Kapusta,
• Rolf Erni,
• Stanislav Moshkalev and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1508–1517, doi:10.3762/bjnano.6.156

• O2 gas and a) laser pulsing [23] or b) low-temperature substrate annealing (up to 50 °C) [24]. The presence of H2O during electron irradiation performed at rt allowed for a total elimination of carbon from Pt–C deposits without affecting the shape [25]. The combination of thermal heating to 300 °C

• , injection of H2 gas and simultaneous electron irradiation led to pure Co deposits [26]. Microstructural changes were observed upon simple 5 keV electron beam curing of FEBID structures. The Pt–C deposits exhibited an increased conductivity by three to four orders of magnitude [27][28]. For W–C deposits an

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

• Deborah Vidick,
• Xiaoxing Ke,
• Michel Devillers,
• Claude Poleunis,
• Arnaud Delcorte,
• Pietro Moggi,
• Gustaaf Van Tendeloo and
• Sophie Hermans

Beilstein J. Nanotechnol. 2015, 6, 1287–1297, doi:10.3762/bjnano.6.133

• nanoparticles, they are damaged by electron irradiation and disappear after the spectra acquisition (Figure 6b). This may explain the EDX point analysis of ultrasmall nanoparticles. The contribution of Pt, if present, is too small or too short-lived to be confirmed. These ultrasmall particles are most probably

Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

• Oleksandr V. Dobrovolskiy,
• Maksym Kompaniiets,
• Roland Sachser,
• Fabrizio Porrati,
• Christian Gspan,
• Harald Plank and
• Michael Huth

Beilstein J. Nanotechnol. 2015, 6, 1082–1090, doi:10.3762/bjnano.6.109

• treatments of samples include annealing in reactive gases [31], electron irradiation [27][28], or a combination of both [30][32][33][34]. Several approaches have already been proposed for the preparation of magnetic nanoparticles and their alloying, in particular, with the purpose of eventually using them

• . The employed purification procedure of heating at 300 °C in H2 atmosphere in conjunction with electron irradiation relies upon the Fischer–Tropsch reaction [30][43]. In this chemical process, cobalt serves as a catalyst, while volatile hydrocarbons and water are produced, effectively oxidizing the

Patterning technique for gold nanoparticles on substrates using a focused electron beam

• Takahiro Noriki,
• Shogo Abe,
• Kotaro Kajikawa and
• Masayuki Shimojo

Beilstein J. Nanotechnol. 2015, 6, 1010–1015, doi:10.3762/bjnano.6.104

• specimen using the amino-undecanethiol method after step (iii), illustrating that the nanoparticles remained in the rectangular area of electron irradiation. Schematic illustration of the formation of a two-dimensional, dense array of gold nanoparticles on a silicon substrate: step (i). Acknowledgements

Fabrication of high-resolution nanostructures of complex geometry by the single-spot nanolithography method

• Alexander Samardak,
• Margarita Anisimova,
• Aleksei Samardak and
• Alexey Ognev

Beilstein J. Nanotechnol. 2015, 6, 976–986, doi:10.3762/bjnano.6.101

• of complex shape. The effect of high-dose electron irradiation on the chemical properties of polymers (resulting in hardening or overexposure) was observed in different types of positive resists: DQN [7], AZ-PF514 [8], and PMMA [9][10]. Poly(methyl methacrylate) (PMMA) is the most prevalent EBL

Observing the morphology of single-layered embedded silicon nanocrystals by using temperature-stable TEM membranes

• Sebastian Gutsch,
• Daniel Hiller,
• Jan Laube,
• Margit Zacharias and
• Christian Kübel

Beilstein J. Nanotechnol. 2015, 6, 964–970, doi:10.3762/bjnano.6.99

• thickness and stoichiometry are below a critical value. Keywords: electron irradiation damage; energy-filtered transmission electron microscopy; membrane; plane view; silicon nanocrystals; size control; size distribution; Introduction Si nanocrystals (Si NC) are interesting for applications in third

• Si plasmon loss energy). Results and Discussion Electron irradiation damage First of all, we focus on a more general observation which mainly concerns the thin film instability during the imaging process. In Figure 1a, a TEM micrograph of sample S1 is presented. In the energy-filtered imaging, the Si

• molecules, which is supported by the observation of defect creation in SiO2 after electron irradiation [34] and a SiO2 thickness dependence on the hole drilling time when exposed to an intense electron probe [35]. Another possible explanation is certainly a preferential sputtering or knock-on of oxygen [36