Silicene, germanene and other group IV 2D materials

• Patrick Vogt

Beilstein J. Nanotechnol. 2018, 9, 2665–2667, doi:10.3762/bjnano.9.248

• beam epitaxy (MBE) [1][2] and at around the same time on zirconium diboride thin films grown on Si(111) substrates by Si segregation through the film [3]. The synthesis of silicene further launched an intensive search for other 2D elemental materials synthesized under ultrahigh vacuum by MBE-like

Magnetism and magnetoresistance of single Ni–Cu alloy nanowires

• Andreea Costas,
• Camelia Florica,
• Elena Matei,
• Maria Eugenia Toimil-Molares,
• Ionel Stavarache,
• Andrei Kuncser,
• Victor Kuncser and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2018, 9, 2345–2355, doi:10.3762/bjnano.9.219

• -resistance data in corresponding magnetic hysteresis loops can be applied, opening the way for an easier experimental investigation of magnetization reversal in ferromagnetic single nanowires. Information about magnetic parameters and phase segregation in single nanowires has been obtained by exploiting the

• shown in Figure 3. SNW0 was left out because it belongs to the sample with the highest Cu content, where a strong segregation was already confirmed in [27]. Assuming Stoner–Wohlfarth-type magnetic behavior, at least in the case of perpendicular geometry (where magnetoresistance effects are present), the

• , the only explanation for the very slight decrease of the saturation field from 0.36 T in sample SNW3 (92% Ni) to only 0.34 T in sample SNW1 (54% Ni) is an enhanced segregation of Ni and Cu, with the formation of a segmented structure consisting of Cu and Ni volumes. The Ni-enriched cylindrical

Block copolymers for designing nanostructured porous coatings

• Roberto Nisticò

Beilstein J. Nanotechnol. 2018, 9, 2332–2344, doi:10.3762/bjnano.9.218

• Figure 1B, by increasing the volume fraction, f, of one of the blocks, the microdomain arrangement changed from closely packed spheres (CPSs), to body centered cubic spheres (Q229), to hexagonally packed cylinders (H), to bicontinuous gyroid (Q230, which becomes unstable at high values of segregation

Nanoscale electrochemical response of lithium-ion cathodes: a combined study using C-AFM and SIMS

• Jonathan Op de Beeck,
• Nouha Labyedh,
• Alfonso Sepúlveda,
• Valentina Spampinato,
• Alexis Franquet,
• Thierry Conard,
• Philippe M. Vereecken,
• Wilfried Vandervorst and
• Umberto Celano

Beilstein J. Nanotechnol. 2018, 9, 1623–1628, doi:10.3762/bjnano.9.154

• profile of lithium as measured by SIMS on the same area (scale bar 2 µm). Both C-AFM and SIMS indicate the segregation of the film in phases with different local chemistry and electrical conduction. Additionally, their strong correlation reveals the inherent link between the varying Li content and

Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy

• Alexey D. Bolshakov,
• Alexey M. Mozharov,
• Georgiy A. Sapunov,
• Igor V. Shtrom,
• Nickolay V. Sibirev,
• Vladimir V. Fedorov,
• Evgeniy V. Ubyivovk,
• Maria Tchernycheva,
• George E. Cirlin and
• Ivan S. Mukhin

Beilstein J. Nanotechnol. 2018, 9, 146–154, doi:10.3762/bjnano.9.17

• barrier on the NW sidewalls and lateral growth occurs. From the other point-of-view, a very high concentration of Si doping in the case of N-rich GaN planar growth leads to Si surface segregation [31]. When the segregation occurs, the concentration of Si atoms at the crystal surface can be an order of

Growth model and structure evolution of Ag layers deposited on Ge films

• Arkadiusz Ciesielski,
• Lukasz Skowronski,
• Ewa Górecka,
• Jakub Kierdaszuk and
• Tomasz Szoplik

Beilstein J. Nanotechnol. 2018, 9, 66–76, doi:10.3762/bjnano.9.9

• ) and X-ray diffraction (XRD) measurements proved that segregation of germanium into the surface of the silver film is a result of the gradient growth of silver crystals. The free energy of Ge atoms is reduced by their migration from boundaries of larger grains at the Ag/SiO2 interface to boundaries of

• smaller grains near the Ag surface. Annealing at different temperatures and various durations allowed for a controlled distribution of crystal dimensions, thus influencing the segregation rate. Furthermore, using ellipsometric and optical transmission measurements we determined the time-dependent

• evolution of the film structure. If stored under ambient conditions for the first week after deposition, the changes in the transmission spectra are smaller than the measurement accuracy. Over the course of the following three weeks, the segregation-induced effects result in considerably modified

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• planar type when the nanotubes are oriented along the matrix director, and the homeotropic type when the nanotubes are perpendicular to the director). The possibility of a redistribution of the nanotube concentration (segregation effect) is shown. The fields of orientational transitions between uniform

• first or of second order depending on the carbon nanotubes segregation intensity. Keywords: carbon nanotubes; liquid crystal; magnetic field; orientational transitions; soft coupling; Introduction In recent years suspensions of anisometric particles in liquid crystals have become of great interest for

• k is the ratio of Frank's constants of the LC. The parameter κ is the square of the ratio between two characteristic lengths, i.e., layer thickness L and segregation length [3][40]. The characteristic size of the concentration redistribution region, LS, can be determined from the balance of the

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

• presented and discussed above were not satisfying. This attempt resulted in a density of CNTs as 2-dimensional deposits (Fe rectangles) and was not sufficient to form the desired forest material. An important point in this regard is probably diffusion along with Oswald ripening and segregation of the Fe

• discussed, this can be conclusively explained by the reduction of the Fe mobility on the Al2O3 surface, resulting in less Fe coarsening or segregation during the heating process, thus leaving more catalytically active Fe sites for CNT growth [29]. According to the literature, the Al2O3 itself does not

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• between the magnetic and liquid crystal subsystems in the absence of segregation. Ferrocholesteric in a Shear Flow and a Magnetic Field For a uniform stationary shear flow with a constant velocity gradient, the incompressibility condition (Equation 3) is fulfilled identically, and the equation of motion

Ta₂N₃ nanocrystals grown in Al₂O₃ thin layers

• Krešimir Salamon,
• Maja Buljan,
• Iva Šarić,
• Mladen Petravić and
• Sigrid Bernstorff

Beilstein J. Nanotechnol. 2017, 8, 2162–2170, doi:10.3762/bjnano.8.215

• Figure 1, the GISAXS patterns reveal various types of additional scattering such as rings, lobes or strong scattering concentrated in very small angles for the MLs annealed at 900 °C. These small-angle scattering patterns clearly demonstrate a thermally induced segregation of the Ta(N) and Al2O3

• and shrinks towards smaller angles with increasing annealing temperature. This indicates an enlargement of the NPs and consequently a stronger segregation of the Ta and Al2O3 components in the metallic layers resulting in a higher density contrast. Note that up to 800 °C the original Bragg sheets

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• [23][24]. Be has been the main choice to produce p-type GaAs layers and nanowires grown by molecular beam epitaxy (MBE) [25][26][27][28]. However, severe drawbacks like segregation at high concentration, a large diffusion coefficient prohibiting abrupt doping profiles and high toxicity have motivated

High-stress study of bioinspired multifunctional PEDOT:PSS/nanoclay nanocomposites using AFM, SEM and numerical simulation

• Alfredo J. Diaz,
• Hanaul Noh,
• Tobias Meier and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2069–2082, doi:10.3762/bjnano.8.207

• -correlation was performed to eliminate the drift effects. Figure 3 shows the electro-mechanical response of the transparent samples. The out-of-plane current showed a different distribution for the three samples, especially for MTM. The MTM nanocomposite shows segregation in the current and mechanical

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• made as thin as 50 nm without any segregation at the graphene CVD temperature (≈1000 °C), because of the higher melting point of Mo (2623 °C) compared to that of other conventional catalysts such as Cu (1085 °C) or Ni (1455 °C). Moreover, this allows a pre-patterning the film for the selective growth

Needs and challenges for assessing the environmental impacts of engineered nanomaterials (ENMs)

• Michelle Romero-Franco,
• Hilary A. Godwin,
• Muhammad Bilal and
• Yoram Cohen

Beilstein J. Nanotechnol. 2017, 8, 989–1014, doi:10.3762/bjnano.8.101

Modeling of the growth of GaAs–AlGaAs core–shell nanowires

• Qian Zhang,
• Peter W. Voorhees and
• Stephen H. Davis

Beilstein J. Nanotechnol. 2017, 8, 506–513, doi:10.3762/bjnano.8.54

• mechanism responsible for the segregation of Al atoms in the shells. It is found that the mobility difference of the atoms on the {112} and {110} facets together determine the non-uniform concentration of the atoms in the shell. In particular, even though the mobility of Al on {110} facets is smaller than

• nanowires? The other issue is the mechanism responsible for the segregation of Al atoms in the shells. More specifically, under certain deposition conditions, Al atoms move slower than Ga atoms along the {110} facets [6]. If the atoms move from {110} to {112} facets, then the Al atoms should be left behind

• transient growth (Figure 7b). The configuration obtained in the numerical simulation is very close to that seen experimentally (Figure 7a). Besides the dot configuration shown in Figure 7b, Heiss et al. [2] also observed the segregation of Al in the shell of the nanowire (see the Al concentration shown in

Obtaining and doping of InAs-QD/GaAs(001) nanostructures by ion beam sputtering

• Sergei N. Chebotarev,
• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Elena N. Zhivotova,
• Georgy A. Erimeev and
• Marina L. Lunina

Beilstein J. Nanotechnol. 2017, 8, 12–20, doi:10.3762/bjnano.8.2

• . The increase in the impurity concentration along the direction of growth for values of RGaAs/SnTe between 100 and 101 can be explained by a weakly pronounced impurity segregation [36][37][38]. Evaporation of the solid SnTe source of can occur in the form of elementary Sn, elementary Te or molecules

• /SnTe ≈ 100–101 is explained by segregation that is mainly caused by existence of Te in the ligature source. The presence of impurities in the GaAs barrier layer increases the intensity of photoluminescence peaks of the ground and excited states of the quantum dots. The appearance of donor levels in the

Ferromagnetic behaviour of ZnO: the role of grain boundaries

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185

• multilayer grain boundary segregation. Keywords: ferromagnetism; grain boundaries; zinc(II) oxide (ZnO); Review Introduction In 2000 the seminal work of Tomasz Dietl et al. appeared [1]. In this work it was predicted theoretically that many semiconductor oxides can become ferromagnetic (FM) if one dopes

• . Those cs values do not exceed few percent, even at high temperatures. In several micro- and nanograined materials the overall solubility exceeds the cs value [39][40][41][42][43][44]. Already in 1957, McLean [45] proposed the idea that grain boundary segregation of a second component can change the

• sintered (nano)powders contain less GBs, the main defects are free surfaces. In such samples the overall solubility also increases, but now so drastically as in poreless polycrystals [46][47]. Can the monolayer grain boundary or surface segregation ensure such a high increase of solubility? We estimated

A new approach to grain boundary engineering for nanocrystalline materials

• Shigeaki Kobayashi,
• Sadahiro Tsurekawa and
• Tadao Watanabe

Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176

• , hardness, and the control of segregation-induced intergranular brittleness and intergranular fatigue fracture in electrodeposited nickel and nickel alloys with initial submicrometer-grained structure. A new approach to GBE based on fractal analysis of grain boundary connectivity is proposed to produce high

• grain boundaries and triple junctions. This is often associated with the nonequilibrium deformation of microstructures introduced by severe plastic deformation (SPD) with less thermal stability, excess structural defects and chemical composition by segregation to grain boundaries and interfaces [12][15

• . Engineering applications were successfully achieved first by Aust, Palumbo, Erb and their coworkers [31][32] and then by the authors of this work [33][34][35]. The nonequilibrium structure, structural defect and chemical composition by segregation as well as grain boundary character as the importance of grain

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

• Ana C. S. Alcântara,
• Margarita Darder,
• Pilar Aranda and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1772–1782, doi:10.3762/bjnano.7.170

• medium was firstly tried for the preparation of zein–montmorillonite biohybrids (synthesis 1). In an alternative synthetic approach (synthesis 2) the clay was dispersed in water, favoring the formation of a swollen phase, and zein was treated with pure ethanol to provoke its segregation in two phases

Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

• few defects [134]. Chemical vapor deposition (CVD). The CVD method is commonly used to produce large-area uniform graphene films [77][135]. Similar to the CVD method used to grow CNTs, graphene can be grown from gases containing C on catalytic metal surfaces or by surface segregation of C dissolved in

• metals such as Fe [136], Ni [137], Co, Pt and Pd [138]. The pioneer who discovered single layer graphite on Pt was S. Hagstrom in 1965 [139], but the first to interpret it as a single layer was J. W. May in 1969 [140]. The CVD and surface segregation methods can also coexist causing the carbon atoms

Counterion effects on nano-confined metal–drug–DNA complexes

• Nupur Biswas,
• Sreeja Chakraborty,
• Alokmay Datta,
• Munna Sarkar,
• Mrinmay K. Mukhopadhyay,
• Mrinal K. Bera and
• Hideki Seto

Beilstein J. Nanotechnol. 2016, 7, 62–67, doi:10.3762/bjnano.7.7

• counterions present in a buffer. X-ray reflectivity at and away from the Cu K absorption edge and atomic force microscopy studies reveal that confinement segregates the drug molecules preferentially in a top layer of the DNA film, and counterions enhance this segregation. Keywords: confinement; metal–drug

• states [6]. Again, a mixture of DNA and other macromolecules undergoes spontaneous segregation and organization under micrometre-scale confinement [7]. Regarding confinement effects at the nanometer scale, we have observed that in absence of counterions DNA molecules form layered structures aligned

• more enhanced in the case of the buffer film, indicating counterions enhance the Cu proportion in this layer. This suggests that a drug–DNA segregation occurs with buffering leaving more drug–metal composites at the surface increasing its roughness and clustering as observed from AFM topography (Figure

Two-phase equilibrium states in individual Cu–Ni nanoparticles: size, depletion and hysteresis effects

• Aram S. Shirinyan

Beilstein J. Nanotechnol. 2015, 6, 1811–1820, doi:10.3762/bjnano.6.185

• nucleation in finite systems [14] and for grain boundary segregation problem as a successful approach to stabilize nanocrystalline materials against grain growth [15][16][17]. Chemical depletion is similar to oxygen starvation in medicine (also called as hypoxia) [18]. The origin of hypoxia is the same

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

• absorption and emission devices require doping [4][5]. In this context, conventional bulk doping techniques must be adapted, given the large surface to volume ratio of nanostructures, surface segregation of dopant atoms is a severe drawback. Therefore detailed knowledge and control of the physical and

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

• be used for the study of interfaces in carbon-based nanohybrids. For example, in [97] an attempt is given to resolve the interface of CNT–TiO2 hybrids. Segregation or mixed metal–carbon phases at the interface of nanohybrids can be evaluated. Additionally, the introduction of the monochromator and

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

• irradiation dose of these regions and hence a slightly less reticulated carbon network which facilitates segregation at many places. For laser-induced heating we found the same phenomenon of surface precipitation of Cu nanocrystals although the annealing time was only one minute. Also the same trend in the

• the resistance-vs-temperature behavior of the samples would be stable. Here we focused on a proof of concept study. Conclusion We have shown that nanostructural changes were induced in Cu–C FEBID material from Cu(I) and Cu(II) precursors upon post-growth annealing causing the segregation and

• obtained from (hfac)CuVTMS and (hfac)CuDMB. The as-deposited materials were non-conductive. The transition into conductive material as well as the segregation and precipitation of the copper atoms occur upon conventional or laser heating. The surface precipitation of copper nanocrystals upon annealing