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

• the grain boundary voids, thus increasing the effective density (Figure 2, right). It is also worth noting, that in the case of modeling results of XRR measurements performed 3 days after the deposition (Figure 3a,c,e,g), it was necessary to consider a separate Ge interlayer between SiO2 substrate and

• segregation is completed, a competing process of grain boundary diffusion can still modify the distribution of Ge atoms within the silver layer, influencing the density slope and optical parameters [28]. For all non-annealed samples, regardless of the Ge-to-Ag ratio, the changes in transmission from one stage

Exploring wear at the nanoscale with circular mode atomic force microscopy

• Olivier Noel,
• Aleksandar Vencl and
• Pierre-Emmanuel Mazeran

Beilstein J. Nanotechnol. 2017, 8, 2662–2668, doi:10.3762/bjnano.8.266

• diameter of the circular displacement ranges from 0.16 µm to 3 µm. Thus, the CM-AFM allows local probing of materials. In this way, it is possible to investigate wear of metallic materials while avoiding the grain boundary effects. Considering the CM-AFM, the lateral force signal (also referred as the

Nanoprofilometry study of focal conic domain structures in a liquid crystalline free surface

• Anna N. Bagdinova,
• Evgeny I. Demikhov,
• Nataliya G. Borisenko and
• Sergei M. Tolokonnikov

Beilstein J. Nanotechnol. 2017, 8, 2544–2551, doi:10.3762/bjnano.8.254

• with twist grain boundary (TGB)-like structures [18][19][20] because of some interdomain regions, which can explain the holes in the FCD-structured surface. We could expect some pattern formation starting from the nematic phase. The surface of the isotropic liquid and the nematic phase of 8CB revealed

Molecular dynamics simulations of nanoindentation and scratch in Cu grain boundaries

• Shih-Wei Liang,
• Ren-Zheng Qiu and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2017, 8, 2283–2295, doi:10.3762/bjnano.8.228

• scratch conditions were studied by molecular dynamics (MD) simulations. The type of grain boundary is the main factor in the control of the substrate atoms with respect to the size of dislocations since the existence of the grain boundary itself restricts the movement associated with dislocations. In this

• work, we analyzed the transverse and vertical grain boundaries for different angles. From the simulation results, it was found that the sample with a transverse grain boundary angle of 20° had a higher barrier effect on the slip band as compared to samples with other angles. Moreover, the

• nanoindentation results (i.e., indentation on the upper area) of the vertical grain boundary showed that the force was translated along the grain boundary, thereby producing intergranular fractures. Keywords: indentation; molecular dynamics; nanograin boundary; nanoscratch; Introduction The recent developments

Process-specific mechanisms of vertically oriented graphene growth in plasmas

• Subrata Ghosh,
• Shyamal R. Polaki,
• Niranjan Kumar,
• Sankarakumar Amirthapandian,
• Mohamed Kamruddin and
• Kostya (Ken) Ostrikov

Beilstein J. Nanotechnol. 2017, 8, 1658–1670, doi:10.3762/bjnano.8.166

• samples is calculated from the empirical Equation 3 [54]: where ωG is the position of the G peak. The sp3 content of the samples is found to be in the range of 19 to 22%, and is considered to be localized at “in-wall-boundary” and “in-grain-boundary” regions [56]. Therefore, it is possible to tune the

• resistance of 0.98 kΩ/sq is observed for the VGNs grown at 800 °C. The lowest sheet resistance of 0.6 kΩ/sq is obtained for the film grown at a distance of 10 cm from the plasma source, which is lower than that of CVD-grown planar graphene with eight layers (0.77 kΩ/sq) [64]. Grain boundary and edge defects

• and disordered carbon, and mainly the sp3 content play key roles in determining the resistivity [9]. Here, the high resistivity of the sample grown at 600 °C can be explained by grain boundary and edge defects of NG, which diminish electron mobility. On the other hand, higher growth temperatures

The integration of graphene into microelectronic devices

• Guenther Ruhl,
• Sebastian Wittmann,
• Matthias Koenig and
• Daniel Neumaier

Beilstein J. Nanotechnol. 2017, 8, 1056–1064, doi:10.3762/bjnano.8.107

• property is the density of defects. In the case of good quality graphene it is mainly determined by the density of grain boundaries between the single-crystalline domains [34]. If a grain boundary lies inside the active region of a graphene device it reduces the device performance by locally changing the

Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting

• Sun-Kyu Lee,
• Sori Hwang,
• Yoon-Kee Kim and
• Yong-Jun Oh

Beilstein J. Nanotechnol. 2017, 8, 1049–1055, doi:10.3762/bjnano.8.106

• solid-state dewetting. The dewetting processes of polycrystalline metallic films on smooth and topographic substrates are well known. On smooth substrates, solid-state dewetting of the film occurs with film thinning and hole formation at a grain boundary (GB) triple junction, followed by retraction of

Diffusion and surface alloying of gradient nanostructured metals

• Zhenbo Wang and
• Ke Lu

Beilstein J. Nanotechnol. 2017, 8, 547–560, doi:10.3762/bjnano.8.59

• , different surface alloying processes, such as nitriding and chromizing, have been modified significantly, and some diffusion-related properties have been enhanced. Finally, the perspectives on current research in this field are discussed. Keywords: diffusion; gradient nanostructures; grain boundary

Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature

• Tapas Ghosh and
• Biswarup Satpati

Beilstein J. Nanotechnol. 2017, 8, 425–433, doi:10.3762/bjnano.8.45

• a grain boundary grooving mechanism during thermal annealing [32][33]. Further annealing results in Oswald ripening [34][35], where the atoms diffuse from smaller to larger nanoparticles and form larger copper clusters. The agglomeration of copper particles was observed in the earlier observations

• observed that when the substrate or the Cu film is exposed to air, the agglomeration is hindered [34]. Such retardation in copper agglomeration is caused as the oxidation in the grain boundaries retards the diffusion in the grain boundaries and also affects the grain boundary grooving [34][36][37]. Again

Annealing-induced recovery of indents in thin Au(Fe) bilayer films

• Anna Kosinova,
• Ruth Schwaiger,
• Leonid Klinger and
• Eugen Rabkin

Beilstein J. Nanotechnol. 2016, 7, 2088–2099, doi:10.3762/bjnano.7.199

• contribution of grain boundaries to the depression formation. Indeed, an abrupt change of the surface slope is an essential attribute of the grain boundary groove, indicating a balance of surface and grain boundary energies at the triple line [7][20]. Our EBSD observations have demonstrated that significant

• grain growth and texture sharpening had occurred in the film upon annealing, so that either a single grain boundary or no grain boundary at all were present in the immediate vicinity of the indents. We believe that the depressions were formed only in the cases when a grain boundary was available near

• dislocation loops is non-conservative, it generates a flux of excess vacancies. The vacancies can reach the film-substrate interface and the nearby grain boundary, which both can serve as vacancy sinks. The annihilation of vacancies at the film-substrate interface leads to the slight decrease of the film

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

• qualitatively) where and when the ferromagnetism appears in zinc oxide. We supposed that ferromagnetic behaviour of pure and doped ZnO is controlled by grain boundaries (GBs) and appears only if the grain boundary network (the “ferromagnetic foam”) is dense enough [7]. Our first results concerning the role of

• ][8][9]. In each of the five parts of Figure 1 the temperature is plotted along the vertical axis. It is either the synthesis temperature or the temperature of last annealing of the oxides. The grain boundary specific area sGB is given in the horizontal axis. sGB is the area of GBs in a unit volume

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

• Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan, Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110004, China, Formerly, Tohoku University, Sendai, Japan 10.3762/bjnano.7.176 Abstract A new approach to grain boundary engineering (GBE) for

• effectiveness of precisely controlled grain boundary microstructures (quantitatively characterized by the grain boundary character distribution (GBCD) and grain boundary connectivity associated with triple junctions) has been revealed for recent achievements in the enhancement of grain boundary strengthening

• , 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

Effect of triple junctions on deformation twinning in a nanostructured Cu–Zn alloy: A statistical study using transmission Kikuchi diffraction

• Silu Liu,
• Xiaolong Ma,
• Lingzhen Li,
• Liwen Zhang,
• Patrick W. Trimby,
• Xiaozhou Liao,
• Yusheng Li,
• Yonghao Zhao and
• Yuntian Zhu

Beilstein J. Nanotechnol. 2016, 7, 1501–1506, doi:10.3762/bjnano.7.143

• both the scientific understanding and practical design of nanostructured materials. Previously, triple junctions have been reported to play a critical role in other deformation mechanisms in nanostructured materials, like grain rotation [16] and grain boundary sliding [17]. Additionally, earlier

• twin can be clearly observed, as shown in frame B of Figure 2a. The third case is shown in Figure 3c: when the twinning propagates to the grain boundary and the twin domain thereby becomes large enough to cover part of a grain, only one coherent twin boundary appears in the grain. In this case, a red

Fast diffusion of silver in TiO₂ nanotube arrays

• Wanggang Zhang,
• Yiming Liu,
• Diaoyu Zhou,
• Hui Wang,
• Wei Liang and
• Fuqian Yang

Beilstein J. Nanotechnol. 2016, 7, 1129–1140, doi:10.3762/bjnano.7.105

• diffusion of Ag atoms on the outmost surface of the TiO2 nanotubes in the temperature range of 300 to 500 °C is 157 kJ/mol, which is less than that for the lattice diffusion of Ag and larger than that for the grain boundary diffusion. The diffusion of Ag atoms leads to the formation of Ag nanocrystals on

• for the migration/diffusion of Ag atoms on the outmost surface of the TiO2 nanotubes in the temperature range of 300 to 500 °C. There are studies on the diffusion of Ag, including self-diffusion, grain boundary diffusion, and diffusion of Ag in amorphous TiO2 films. Table 1 summarises the data

• diffusivity for the grain boundary diffusion of Ag with the activation energy being less than that for the lattice diffusion of Ag and larger than that for the grain boundary diffusion. Such a result suggests that both the grain boundary diffusion of Ag and the interface diffusion on the surface of the TiO2

In situ observation of deformation processes in nanocrystalline face-centered cubic metals

• Aaron Kobler,
• Christian Brandl,
• Horst Hahn and
• Christian Kübel

Beilstein J. Nanotechnol. 2016, 7, 572–580, doi:10.3762/bjnano.7.50

• situ straining inside a transmission electron microscope was applied to study the deformation of nanocrystalline PdxAu1−x thin films. This combination enables direct imaging of simultaneously occurring plastic deformation processes in one experiment, such as grain boundary motion, twin activity and

• defects into a sharp small angle GB (Figure 2, 6.4%) upon unloading by fracture is, however, consistent with the accumulation of a residual dislocation network in the nanograin during deformation, which condenses into a small angle grain boundary. Moreover, the reversible GB motion observed here can also

• grain boundary at 0% strain and the migration of the triple line half way through the grain during tensile loading. Since the Σ9 misorientation can be generated by a sequence of two distinct twin variants [46][47], Figure 4d illustrates schematically possible twin morphologies in one grain: the upper

Determination of the compositions of the DIGM zone in nanocrystalline Ag/Au and Ag/Pd thin films by secondary neutral mass spectrometry

• Gábor Y. Molnár,
• Shenouda S. Shenouda,
• Gábor L. Katona,
• Gábor A. Langer and
• Dezső L. Beke

Beilstein J. Nanotechnol. 2016, 7, 474–483, doi:10.3762/bjnano.7.41

• by grain boundary diffusion-induced grain boundary migration is investigated by secondary neutral mass spectrometry depth profiling in Ag/Au and Ag/Pd nanocrystalline thin film systems. It is shown that the compositions in zones left behind the moving boundaries can be determined by this technique if

• the process takes place at low temperatures where solely the grain boundary transport is the contributing mechanism and the gain size is less than the half of the grain boundary migration distance. The results in Ag/Au system are in good accordance with the predictions given by the step mechanism of

• grain boundary migration, i.e., the saturation compositions are higher in the slower component (i.e., in Au or Pd). It is shown that the homogenization process stops after reaching the saturation values and further intermixing can take place only if fresh samples with initial compositions, according to

Plasticity-mediated collapse and recrystallization in hollow copper nanowires: a molecular dynamics simulation

• Amlan Dutta,
• Arup Kumar Raychaudhuri and
• Tanusri Saha-Dasgupta

Beilstein J. Nanotechnol. 2016, 7, 228–235, doi:10.3762/bjnano.7.21

• tendency of reducing the grain boundary to grain volume ratio [1][2]. Another example is that of the nanoparticles exhibiting the propensity of sintering to reduce the free surface through enhanced area of inter-particle contact [3][4]. Perhaps the most interesting example is that of Rayleigh-like

A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials

• Daniela Lehr,
• Markus R. Wagner,
• Johanna Flock,
• Julian S. Reparaz,
• Clivia M. Sotomayor Torres,
• Alexander Klaiber,
• Thomas Dekorsy and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2015, 6, 2161–2172, doi:10.3762/bjnano.6.222

• contribution while the semicircle in the low frequency region is assigned to grain boundary contribution [81]. Because only one single semicircle at low frequencies is present in Figure 6, it can be concluded that grain-boundary resistance dominates over grain resistance. The resistance values of the Cl@ZnO

• the grain-boundary influence can significantly differ from sample to sample. This can also be seen in Figure S6b (Supporting Information File 1). For higher Cl content, when the tendency for the formation of separated particles is more pronounced (Figure 3), the resistivity raises due to the enhanced

• could be proven by several methods, that the desired materials were obtained, due to the current, powder-like nature, the electronic properties are yet dominated by grain boundary effects. Therefore, future research in this field will address the synthesis of thin films minimizing the amount of grain

Effect of SiN_x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO₂ films obtained by sol–gel dip coating and reactive magnetron sputtering

• Mohamed Nawfal Ghazzal,
• Eric Aubry,
• Nouari Chaoui and
• Didier Robert

Beilstein J. Nanotechnol. 2015, 6, 2039–2045, doi:10.3762/bjnano.6.207

• various substrates. Nam et al. reported that the Na+ ions in the TiO2 films induce an increase in their crystallite size [4]. The diffusion of the ions at the grain boundary during the heat treatment is in competition with the nucleation/growth of the anatase crystallite, which induces an increase in the

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

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

• Figure 5e–h, where a grain boundary is imaged on a single graphene layer using annular dark field scanning transmission electron microscopy (ADF-STEM) acquired at 60 kV. An extensive arrangement of the 5–7 pairs together with distorted hexagons is revealed (Figure 5g,h) [62]. It can be deduced that

High sensitivity and high resolution element 3D analysis by a combined SIMS–SPM instrument

• Yves Fleming and
• Tom Wirtz

Beilstein J. Nanotechnol. 2015, 6, 1091–1099, doi:10.3762/bjnano.6.110

• the grain boundary walls of the γ′ precipitate phase. As we know from literature that 52Cr is not present in the γ′ phase [19], a fraction of the 52Cr16O− ions originating from the faster sputtering γ matrix are first deposited at the boundary wall of the Ni3Al precipitate phase before finally being

On the structure of grain/interphase boundaries and interfaces

• K. Anantha Padmanabhan and
• Herbert Gleiter

Beilstein J. Nanotechnol. 2014, 5, 1603–1615, doi:10.3762/bjnano.5.172

• sufficient, condition. For example, not all properties associated with grain boundaries (GBs) in all face-centered cubic (fcc) metals, e.g., the presence or absence of an orientation-dependence of the grain boundary energy, are identical, although the geometry of their atomic structure is the same. In this

• the experiments are on boundaries of metallic materials. These restrictions require a careful consideration whether an approach based on crystallographic concepts is applicable. In a grain boundary of a polycrystalline material, the structure is periodic because the boundary conditions, i.e., those

• relationships are not necessarily CSLs. (However, some low energy grain boundary orientations may have coincident atom sites, which would qualify them as CSLs.) This has been proved in several experiments involving relaxed boundaries. For example, in rotating sphere experiments low energy relationships varied

Formation of Cu_xAu_1−x phases by cold homogenization of Au/Cu nanocrystalline thin films

• Alona Tynkova,
• Gabor L. Katona,
• Gabor A. Langer,
• Sergey I. Sidorenko,
• Svetlana M. Voloshko and
• Dezso L. Beke

Beilstein J. Nanotechnol. 2014, 5, 1491–1500, doi:10.3762/bjnano.5.162

• , which leads to formation of intermetallic phases. Different compounds can be formed depending on the initial thickness ratio. The process starts with grain boundary interdiffusion, which is followed by a formation of reaction layers at the grain boundaries that leads to the motion of the newly formed

• interfaces perpendicular to the grain boundary plane. Finally, the homogenization finishes when all the pure components have been consumed. The process is asymmetric: It is faster in the Au layer. In Au(25nm)/Cu(50nm) samples the final state is the ordered AuCu3 phase. Decrease of the film thicknesses, as

• using a simple model the interface velocity in both the Cu and Au layers were estimated from the linear increase of the average composition and its value is about two orders of magnitude larger in Au (ca. 10−11 m/s) than in Cu (ca. 10−13 m/s). Keywords: Cu/Au; grain boundary diffusion; nanofilms of

Scale effects of nanomechanical properties and deformation behavior of Au nanoparticle and thin film using depth sensing nanoindentation

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2014, 5, 822–836, doi:10.3762/bjnano.5.94

• disrupt the regular atomic arrangements in the lattice planes, the so called dislocations. Figure 1 shows for a polycrystalline material, as an example, dislocations in the grain originating from the grain boundary and the grain interior, from a multiplication of existing dislocations during loading or

• grain boundary. The stress at the grain boundary is called the pile up stress, given as where τi is the friction stress opposing the movement of the dislocations. The number of dislocations in the pile up in grain A (n1A) is greater than in grain C (n2C) due to the larger size which leads to a greater

• τp. For a slip to occur across the grain boundary, τp must be greater than the critical stress, τcritical. A higher initial τ is therefore required on grain C before the critical stress is reached to allow slip to occur and plastic deformation to continue, which results in a higher yield stress