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Search for "grain boundaries" in Full Text gives 149 result(s) in Beilstein Journal of Nanotechnology.
Molecular dynamics simulations of nanoindentation and scratch in Cu grain boundaries
Beilstein J. Nanotechnol. 2017, 8, 2283–2295, doi:10.3762/bjnano.8.228
- Shih-Wei Liang Ren-Zheng Qiu Te-Hua Fang Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan 10.3762/bjnano.8.228 Abstract The dynamic nanomechanical characteristics of Cu films with different grain boundaries under nanoindentation and
- 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
- conditions using MD simulations. However, the nanomechanical properties of the different types of grain boundaries have been scarcely studied using MD simulations. Therefore, the study of the potential fracture of substrates upon mechanical pressure as a result of the different grain boundaries is of
Process-specific mechanisms of vertically oriented graphene growth in plasmas
Beilstein J. Nanotechnol. 2017, 8, 1658–1670, doi:10.3762/bjnano.8.166
- this study, NG structures were not observed below 600 °C and this is explained by adverse etching of graphene by hydrogen radicals in the plasma, which dominates over the graphene growth at lower temperatures [46]. Figure 1c shows the vertical sheets nucleated from the grain boundaries. This is
- crystallinity to facilitate grain growth in nanocrystalline materials. This trend, clearly shown in Figure 3c, implies that the initial growth of the vertical sheets can be attributed to the relaxation of stress that starts at grain boundaries of NG islands. The higher growth rates at high temperature could be
- with growth temperature suggests that the intrinsic electric field plays a major role in the pronounced vertical growth compared to the effects of stress released at grain boundaries at higher temperature. It is also shown that the morphology (from planar to vertical networks) wetting, and structural
Parylene C as a versatile dielectric material for organic field-effect transistors
Beilstein J. Nanotechnol. 2017, 8, 1532–1545, doi:10.3762/bjnano.8.155
- threshold voltage can be controlled. This effect is mainly attributed to the mechanism of charge trapping at grain boundaries [52]. It was also found in further studies that the growth of C60 on the surface of Parylene C at elevated substrate temperatures leads to the creation of radicals at the interface
- of grain boundaries by the smoothness of the BCB layer. However, it only works when Parylene C/BCB bilayer system is used. By applying a bilayer encapsulation system, the defects in the Parylene C film underneath are blocked by the BCB layer. The permeation path for water vapor and oxygen becomes
Formation of ferromagnetic molecular thin films from blends by annealing
Beilstein J. Nanotechnol. 2017, 8, 1469–1475, doi:10.3762/bjnano.8.146
- with their long axis measuring up to 10 µm. X-ray diffraction studies show that the out-of-plane dimensions of the grains (84 ± 9 nm) are comparable to the target film thickness of 100 nm, which means that no grain boundaries parallel to the substrate plane are expected. Magnetic measurements reveal
A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls
Beilstein J. Nanotechnol. 2017, 8, 1231–1237, doi:10.3762/bjnano.8.124
- through the walls. These oxygen species might also diffuse through the oxidized metal and the grain boundaries existing in the metal film [10]. In any case, the thinner the shell, the larger the amount of reactive oxygen species able to penetrate into the cage. Further investigations into the thin-shell
- could be considered to form the nanocages. For example, sputtering could be used to create nanometer-thick amorphous or polycrystalline films, which are expected to have pores (voids) and diffusion paths (grain boundaries). Note, however, that the sputtering technique typically leads to highly conformal
The integration of graphene into microelectronic devices
Beilstein J. Nanotechnol. 2017, 8, 1056–1064, doi:10.3762/bjnano.8.107
- temperature profile and C/Ni ratio the number of graphene layers can be controlled. However, process control is difficult and Ni grain boundaries can lead to an inhomogeneous thickness distribution of the graphene layer. A similar approach utilizes the diffusion of carbon species from a CVD atmosphere along
- grain boundaries through a copper film to the underlying substrate [30]. As there is no significant solubility of carbon in copper, the film formation is expected to be very inhomogeneous. Alternatively Cu is used as catalytic material to convert a self-assembled monolayer as carbon source at the Cu
- growth substrate, preferably using etch-free methods due to high substrate cost [32], is an interesting option. 2 Intrinsic properties The quality of the graphene material itself is a result of the growth and transfer process and can be influenced by several intrinsic properties. 2.1 Grain boundaries One
Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins
Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88
- to resolve, map, and create nanoscale variations in chemical structure and materials properties will be needed to extend Moore’s law of transistor scaling into the single-digit nanometer regime [7][8]. Nanoscale structure–property characterization of grain boundaries and interboundary materials has
Diffusion and surface alloying of gradient nanostructured metals
Beilstein J. Nanotechnol. 2017, 8, 547–560, doi:10.3762/bjnano.8.59
- activation enthalpy were measured in the nanostructured Cu synthesized by IGC [14][15][16]. And a comparable diffusivity with that of conventional grain boundaries (GBs) was revealed in a nanostructured γ-Fe–Ni alloy prepared by ball milling with subsequent sintering (BMS), while inter-agglomerate boundaries
Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media
Beilstein J. Nanotechnol. 2017, 8, 494–505, doi:10.3762/bjnano.8.53
- of ammonium hydroxide is a significant novelty in the growth of these nanostructures. A high-resolution image of a nanorod shows grain boundaries (Figure 7a) of aggregating nanoparticles and indicates the polycrystalline nature of nanorods. A lattice spacing of 0.20 nm corresponding to the hcp Co(002
Advances in the fabrication of graphene transistors on flexible substrates
Beilstein J. Nanotechnol. 2017, 8, 467–474, doi:10.3762/bjnano.8.50
- lengths on the order of ≈100 µm, suitable for solution sensing applications. This channel size poses a challenge considering that the larger the channel dimension, the higher the effect can be on the device performance due to the material defects (e.g., graphene cracks and grain boundaries, surface
Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature
Beilstein J. Nanotechnol. 2017, 8, 425–433, doi:10.3762/bjnano.8.45
- 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
Template-controlled piezoactivity of ZnO thin films grown via a bioinspired approach
Beilstein J. Nanotechnol. 2017, 8, 296–303, doi:10.3762/bjnano.8.32
- . Thus, in order to obtain reliable data, we chose the intermediate thickness range on the order of 300 nm. For RF-magnetron-sputtered ZnO films it was reported, that thicker films in the range of 1 µm show an increasing piezo-activity [45]. This trend may arise from a lower density of grain boundaries
- and a larger crystal size, both of which are achieved by increasing the film thickness. Using our bioinspired growth, the density of the grain boundaries changes only very little with film thickness and therefore it is not necessary to increase the film thickness much above 250 nm in order to achieve
Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles
Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23
- , we have reported the advantages of using 1D ZnO nanorods compared to nanoparticles in DSSCs using N719 as a photosensitizer [31]. Due to the reduced grain boundaries and direct conjunction pathway, 1D nanorods can diffuse electrons faster than nanoparticles and other morphologies. However
- surface area of the nanoparticles, more CdS was loaded on them than on the nanorods but uncontrolled agglomeration may result in random electron conduction and further may enhance the recombination rate. Whereas, the nanorods (due to their superior one-dimensional structure and reduced grain boundaries
Laser irradiation in water for the novel, scalable synthesis of black TiOx photocatalyst for environmental remediation
Beilstein J. Nanotechnol. 2017, 8, 196–202, doi:10.3762/bjnano.8.21
- surface morphology, as reported by SEM, reveals that after irradiation, the black surface is uniformly covered by small structures (Figure 2 centre). A high magnification image (Figure 2 right) shows that they consist of cavities and grain boundaries. It is worth noting that the nanostructure of the film
- appears similar to the case of irradiation under 1064 nm wavelength [22]. However, in the present condition, the holes on the surface of the irradiated sample appear to be concentrated at the grain boundaries generated on the surface by the laser annealing. RBS spectra clearly show the presence of oxygen
Annealing-induced recovery of indents in thin Au(Fe) bilayer films
Beilstein J. Nanotechnol. 2016, 7, 2088–2099, doi:10.3762/bjnano.7.199
- dissipation and the formation of shallow depressions nearby after subsequent annealing treatments. This annealing-induced evolution of nanoindents was interpreted in terms of annihilation of dislocation loops generated during indentation, accompanied by the formation of nanopores at the grain boundaries and
- film behavior at elevated temperatures. This is because these films exhibit only one type of grain boundaries (Σ3 twin boundary, where Σ is a reciprocal density of coincident sites) and are intrinsically stable against dewetting. The interdiffusion coefficients in the Au(Fe) system have been determined
- which all grain boundaries are of the exact <111>Σ3 type, so-called mazed bicrystalline films [18][19], exhibit a special type of microstructure without triple junctions. The electron backscatter diffraction data obtained on the as-deposited film (not shown here) confirmed that only the near-<111>Σ3
Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers
Beilstein J. Nanotechnol. 2016, 7, 2057–2064, doi:10.3762/bjnano.7.196
- hexagonally ordered within grain boundaries. Small voids between grains result from the self-assembly process. We masked voids in five SEM images at different sample locations, neglecting voids smaller than 25 nm2, as an upper limit for tolerances in interparticle distance variations. On average, these voids
Ferromagnetic behaviour of ZnO: the role of grain boundaries
Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185
- that ferromagnetism is not an intrinsic property of the ZnO crystalline lattice but is that of ZnO/ZnO grain boundaries. If a ZnO polycrystal contains enough grain boundaries, it can transform into the ferromagnetic state even without doping with “magnetic atoms” such as Mn, Co, Fe or Ni. However, such
- doping facilitates the appearance of ferromagnetism in ZnO. It increases the saturation magnetisation and decreases the critical amount of grain boundaries needed for FM. A drastic increase of the total solubility of dopants in ZnO with decreasing grain size has been also observed. It is explained by the
- 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
A new approach to grain boundary engineering for nanocrystalline materials
Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176
- boundary microstructures have been seriously considered according to the almost established approach to GBE. This approach has been increasingly recognized for the development of high performance nanocrystalline materials with an extremely high density of grain boundaries and triple junctions. The
- structure, and conventional grain size range. It is evident that the much higher strength of nanocrystalline materials compared to ordinary polycrystals originates from the extensive interaction between grain boundaries and dislocations. On the other hand, poor ductility and severe brittleness of
- 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
Effect of triple junctions on deformation twinning in a nanostructured Cu–Zn alloy: A statistical study using transmission Kikuchi diffraction
Beilstein J. Nanotechnol. 2016, 7, 1501–1506, doi:10.3762/bjnano.7.143
- mechanisms that can simultaneously improve both strength and ductility [5][6][9][10][11]. Consequently, deformation twinning in nanostructured metals has received extensive attention in recent years [10]. Among all of the twinning mechanisms in nanocrystalline materials, partial mission from grain boundaries
- has been found as the primary mechanism from both simulations [12][13] and experiments [14][15]. However, it still remains unclear whether such emissions from grain boundaries have any preference for sites with specific character such as triple junctions. This problem is of significant importance to
- studies revealed that triple junctions were energetically more active than grain boundaries [18] and they were able to emit and absorb free volumes upon deformation, which promotes partial emission [12]. Therefore, one may reasonably hypothesize that triple junctions may promote deformation twinning in
Influence of synthesis conditions on microstructure and phase transformations of annealed Sr2FeMoO6−x nanopowders formed by the citrate–gel method
Beilstein J. Nanotechnol. 2016, 7, 1202–1207, doi:10.3762/bjnano.7.111
- atmosphere with predetermined anionic and cationic defectiveness, is problematic [9]. This is due to several factors: the phase purity within the sample, cation and anion vacancies, sample microstructure, chemical composition and thickness of the grain boundaries [10][11][12][13]. Sol–gel technology is a
Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers
Beilstein J. Nanotechnol. 2016, 7, 852–861, doi:10.3762/bjnano.7.77
- MUA SAM (Figure 4a). The grain boundaries between the gold crystallites are clearly visible and the facets are smooth and free of apparent defects. An image of a sample covered with copper(II) oxalate after 16 deposition cycles (Figure 4b) reveals that the material grows as needle-like structures
In situ observation of deformation processes in nanocrystalline face-centered cubic metals
Beilstein J. Nanotechnol. 2016, 7, 572–580, doi:10.3762/bjnano.7.50
- ]. Modified or even unexpected deformation mechanisms are ascribed to the increasing influence of grain boundaries (GBs) on mechanical properties [3][4][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. GB-mediated deformation mechanisms, such as GB sliding and migration, grain growth and rotation [21
- until fracture (Figure 1d). This procedure allows the assignment of the fracture site to the microstructural features (i.e., grain boundaries) (Figure 1c). The direct overlay reveals that the crack behavior is a combination of intragranular fracture with the crack path through a crystallite (white lines
- in Figure 1c) and intergranular fracture with the crack path along grain boundaries (red lines in Figure 1c). The observation of grain growth, fragmentation and recrystallization next to the crack path (Figure 1c,d) suggests that the deformation is both a result of intragranular deformation (related
Determination of the compositions of the DIGM zone in nanocrystalline Ag/Au and Ag/Pd thin films by secondary neutral mass spectrometry
Beilstein J. Nanotechnol. 2016, 7, 474–483, doi:10.3762/bjnano.7.41
- Figure 2 that there is an intensive intermixing, due to diffusion along the grain boundaries, on both sides and the average concentrations at saturation are below 50%. Furthermore, the saturation values of Au in Ag are lower than that of Ag in Au and their values increase with increasing the annealing
Organized films
Beilstein J. Nanotechnol. 2016, 7, 406–408, doi:10.3762/bjnano.7.35
- . On one hand, the domain structure causes grain boundaries, which are almost impossible to remove. Furthermore, the tight packing of alkane chains in classical LB films prohibits the incorporation of foreign molecules with high precision. This fact is a significant disadvantage if one aims to arrange
Synthesis and applications of carbon nanomaterials for energy generation and storage
Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17
- coming from the gas source to diffuse into the metal. The process is very difficult to control, and especially so in polycrystalline metals where the grain boundaries act as nucleation sites for multilayer growth [141]. For this reason, single crystal and atomically smooth metals are usually preferred to
- quality. In fact, the graphene produced is mostly polycrystalline with aperiodic heptagon/pentagon pairs [143] or overlapped bilayer regions [144] at the grain boundaries (Figure 22b). It has also been demonstrated that the presence of grain boundaries can reduce the mechanical and electrical properties
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