Grain Boundary and Misorientation Angle Dependent Thermal Transport in Single-layer MoS2

Nanoscale ◽  
2022 ◽  
Author(s):  
Ke Xu ◽  
Ting Liang ◽  
Zhisen Zhang ◽  
Xuezheng Cao ◽  
Meng Han ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Misorientation Angle ◽  
Thermal Transport ◽  
Single Layer ◽  
Large Area ◽  
Grain Misorientation

Grain boundaries (GBs) are inevitable defects in large-area MoS2 samples but play a key role in their properties, however, the influence of grain misorientation on thermal transport remains largely unknown...

scholarly journals Scattering Theory of Graphene Grain Boundaries

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1660 ◽  
Author(s):  
Francesco Romeo ◽  
Antonio Di Bartolomeo
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Scattering Theory ◽  
Carrier Transport ◽  
Single Layer ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Single Layer Graphene ◽  
Large Area ◽  
Current Conservation

The implementation of graphene-based electronics requires fabrication processes that are able to cover large device areas, since the exfoliation method is not compatible with industrial applications. The chemical vapor deposition of large-area graphene represents a suitable solution; however, it has an important drawback of producing polycrystalline graphene with the formation of grain boundaries, which are responsible for the limitation of the device’s performance. With these motivations, we formulate a theoretical model of a single-layer graphene grain boundary by generalizing the graphene Dirac Hamiltonian model. The model only includes the long-wavelength regime of the charge carrier transport, which provides the main contribution to the device conductance. Using symmetry-based arguments deduced from the current conservation law, we derive unconventional boundary conditions characterizing the grain boundary physics and analyze their implications on the transport properties of the system. Angle resolved quantities, such as the transmission probability, are studied within the scattering matrix approach. The conditions for the existence of preferential transmission directions are studied in relation with the grain boundary properties. The proposed theory provides a phenomenological model to study grain boundary physics within the scattering approach, and represents per se an important enrichment of the scattering theory of polycrystalline graphene. Moreover, the outcomes of the theory can contribute to understanding and limiting the detrimental effects of graphene grain boundaries, while also providing a benchmark for more elaborate techniques.

Beam-Recrystallized Device-Worthy Films of Si on SiO2 via Control of the Grain Boundary Location

1983 ◽  
Vol 23 ◽  
Author(s):  
J.P. Colinge ◽  
D. Bensahel ◽  
M. Alamome ◽  
M. Haond ◽  
C. Leguet
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Laser Annealing ◽  
Ring Oscillators ◽  
Large Area ◽  
Leakage Currents ◽  
Back Gate ◽  
Boundary Location

ABSTRACTDevice-worthy films of silicon on SiO2 have been produced using laser annealing and antireflection stripes. If no seeding is used, grain boundaries will be localized beneath the stripes; with seeding, large-area single crystals can be grown, of uniform <100> orientation. N-channel transistors show a mobility of 620 cm2/V.s and present leakage currents which can be reduced, however, down to a few pA/um when the substrate (back gate) is negatively biased to − 5 V. Ring oscillators have also been made, which oscillate with a delay per stage of 1 nsec.

Motion of Grain Boundaries: Experiments on Bicrystals

2015 ◽  
Vol 5 ◽  
pp. 247-271
Author(s):  
Dmitri A. Molodov
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Misorientation Angle ◽  
Elevated Temperatures ◽  
Activation Enthalpy ◽  
Boundary Migration ◽  
Boundary Energy ◽  
Boundary Plane ◽  
Migration Behavior ◽  
Twist Boundaries

Recent research on grain boundary migration is reviewed. Novel in-situ measuring techniques based on orientation contrast imaging and the experimental results obtained on specially grown bicrystals are presented. Particularly, the investigated faceting and migration behavior of low angle grain boundaries under the curvature force in aluminum bicrystals was addressed. In contrast to the pure tilt boundaries, which remained straight/flat and immobile during annealing at elevated temperatures, mixed tilt-twist boundaries readily assumed a curved shape and steadily moved under the capillary force. Computational analysis revealed that this behavior is due to the inclinational anisotropy of grain boundary energy, which in turn depends on boundary geometry. The migration of planar grain boundaries induced by a magnetic field was measured in bismuth and zinc bicrystals. Various structurally different boundaries were investigated. The results revealed that grain boundary mobility essentially depends on the misorientation angle and the inclination of the boundary plane. Stress driven boundary migration in aluminium bicrystals was observed to be coupled to a tangential translation of the grains. The activation enthalpy of high angle boundary migration was found to vary non-monotonously with misorientation angle, whereas for low angle boundaries the migration activation enthalpy was virtually the same. The motion of the mixed tilt-twist boundaries under stress was observed to be accompanied by both the translation of adjacent grains parallel to the boundary plane and their rotation around the boundary plane normal.

Observations of Interaction Between Magnetic Domain Wall and Grain Boundaries in Fe-3wt%Si Alloy by Kerr Microscopy

1999 ◽  
Vol 586 ◽  
Author(s):  
K. Kawahara ◽  
Y. Yagyu ◽  
S. Tsurekawa ◽  
T. Watanabe
Keyword(s):  
Domain Wall ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Domain Structure ◽  
Misorientation Angle ◽  
Magnetic Domain ◽  
Magnetic Domain Structure ◽  
Magnetic Domain Wall ◽  
Domain Structures ◽  
Grain Boundary Plane

ABSTRACTMagnetic domain structures in Fe-3wt%Si alloy have been observed by a Kerr microscopy to understand the interaction between the magnetic domain wall and grain boundaries. It was found that the domain structures in the vicinity of the grain boundary depend on the misorientation angle; the high angle random boundary disturbs the magnetic domain structure more than the low angle boundary. In addition to the misorientation angle, magnetic domain structures were affected by the inclination of the grain boundary plane. Moreover, dynamic observations of rearrangement of the magnetic domain structure during magnetization revealed that grain boundaries could act as the sink and/or the source for magnetic domains.

scholarly journals Secondary Recrystallization Goss Texture Development in a Binary Fe81Ga19 Sheet Induced by Inherent Grain Boundary Mobility

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1254
Author(s):  
Zhenghua He ◽  
Yuhui Sha ◽  
Ning Shan ◽  
Yongkuang Gao ◽  
Fan Lei ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Misorientation Angle ◽  
Secondary Recrystallization ◽  
Angle Distribution ◽  
Boundary Mobility ◽  
Goss Texture ◽  
Grain Boundary Mobility ◽  
Misorientation Angle Distribution

Secondary recrystallization Goss texture was efficiently achieved in rolled, binary Fe81Ga19 alloy sheets without the traditional dependence on inhibitors and the surface energy effect. The development of abnormal grain growth (AGG) of Goss grains was analyzed by quasi-situ electron backscatter diffraction (EBSD). The special primary recrystallization texture with strong {112}–{111}<110> and weak Goss texture provides the inherent pinning effect for normal grain growth by a large number of low angle grain boundaries (<15°) and very high angle grain boundaries (>45°) according to the calculation of misorientation angle distribution. The evolution of grain orientation and grain boundary characteristic indicates that the higher fraction of high energy grain boundaries (20–45°) around primary Goss grains supplies a relative advantage in grain boundary mobility from 950 °C to 1000 °C. The secondary recrystallization in binary Fe81Ga19 alloy is realized in terms of the controllable grain boundary mobility difference between Goss and matrix grains, coupled with the orientation and misorientation angle distribution of adjacent matrix grains.

scholarly journals A grain boundary model considering the grain misorientation within a geometrically nonlinear gradient-extended crystal viscoplasticity theory

2020 ◽  
Vol 476 (2235) ◽  
pp. 20190581
Author(s):  
Atefeh Alipour ◽  
Stefanie Reese ◽  
Bob Svendsen ◽  
Stephan Wulfinghoff
Keyword(s):  
Free Energy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Nonlinear Crystal ◽  
Geometrically Nonlinear ◽  
Two Dimensional ◽  
Boundary Model ◽  
Grain Misorientation ◽  
Dislocation Density Tensor ◽  
Boundary Strength

The main goal of the current work is to present a grain boundary model based on the mismatch between adjacent grains in a geometrically nonlinear crystal viscoplasticity framework including the effect of the dislocation density tensor. To this end, the geometrically nonlinear crystal viscoplasticity theory by Alipour et al. (Alipour A et al . 2019 Int. J. Plast. 118 , 17–35. ( doi:10.1016/j.ijplas.2019.01.009 )) is extended by a more complex free energy and a geometrical transmissibility parameter is used to evaluate the dislocation transmission at the grain boundaries which includes the orientations of slip directions and slip plane normals. Then, the grain boundary strength is evaluated based on the misorientation between neighbouring grains using the transmissibility parameter. In some examples, the effect of mismatch in adjacent grains on the grain boundary strength, the dislocation transmission at the grain boundaries and the Hall–Petch slope is discussed by a comparison of two-dimensional random-oriented polycrystals and textured polycrystals under shear deformation.

scholarly journals The Structure Effect on Selective Growth in Recrystallization

Texture ◽  
1975 ◽  
Vol 2 (1) ◽  
pp. 35-44 ◽  
Author(s):  
V. Ju. Novikov
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Secondary Recrystallization ◽  
Primary Recrystallization ◽  
Grain Boundary Mobility ◽  
Effective Mobility ◽  
The Matrix ◽  
The Difference ◽  
Grain Misorientation ◽  
Misorientation Angles

The effect of the dependence of grain boundary mobility on misorientation angle and that of structure of the matrix on the growth selectivity during primary and secondary recrystallization are discussed. It was found that the longer is the distance travelled by the growing grain boundaries and the wider the range of the misorientation angles between the new grains and the matrix, the less is the difference between the grain boundary mobilities of the growing grains, necessary for the manifestation of growth selectivity. So during secondary recrystallization the latter is more manifest. In primary recrystallization after moderate deformations, the growth selectivity will be the least obvious when the deformed matrix consists of small differently oriented areas at whose borders new grains nucleate simultaneously. The secondary grain boundaries should be characterized by “effective” mobility, which depends on the number of the adjacent grains and their dimensions, as well as on the growing grain misorientation in relation to these grains. In the small grained material without a texture, the effective boundary mobilities of any grains are equal, and so the growth selectivity in such a material is non-existing.

scholarly journals Effect of light elements impurity atoms on grain boundary diffusion in FCC metals: a molecular dynamics simulation

2020 ◽  
Vol 62 (12) ◽  
pp. 930-935
Author(s):  
G. M. Poletaev ◽  
I. V. Zorya ◽  
R. Yu. Rakitin ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Crystal Lattice ◽  
Grain Boundaries ◽  
Free Volume ◽  
Misorientation Angle ◽  
Light Elements ◽  
Self Diffusion ◽  
Impurity Atoms ◽  
Metal Atoms

Effect of carbon and oxygen impurity atoms on diffusion along the tilt grain boundaries with <100> and <111> misorientation axis in metals with FCC lattice was studied by mean of molecular dynamics method. Ni, Ag, and Al were considered as metals. Interactions of metal atoms with each other were described by many-particle Clery-Rosato potentials constructed within the framework of tight binding model. To describe interactions of atoms of light elements impurities with metal atoms and atoms of impurities with each other, Morse pair potentials were used. According to obtained results, impurities in most cases lead to an increase in self-diffusion coefficient along the grain boundaries, which is caused by deformation of crystal lattice near the impurity atoms. Therefore, additional distortions and free volume are formed along the boundaries. It is more expressed for carbon impurities. Moreover, with an increase in concentration of carbon in the metal, an increase in coefficient of grain-boundary self-diffusion was observed first, and then a decrease followed. This behavior is explained by formation of aggregates of carbon atoms at grain boundary, which leads to partial blocking of the boundary. Oxygen atoms had smaller effect on diffusion along the grain boundaries, which is apparently explained by absence of a tendency to form aggregates and lesser deformation of crystal lattice around impurity. The greatest effect of impurities on self-diffusion along the grain boundaries among the examined metals was observed for nickel. Nickel has the smallest lattice parameter, impurity atoms deform its lattice around itself more than aluminum and silver, and therefore they create relatively more lattice distortions in it and additional free volume along the grain boundaries, which lead to an increase in diffusion permeability. Diffusion coefficients along the high-angle boundaries with misorientation angle of 30° turned out to be approximately two times higher than along low-angle boundaries with a misorientation angle of 7°. Diffusion along the <100> grain boundaries flowed more intensively than along the <111> boundaries.

scholarly journals Scattering Theory of Graphene Grain Boundaries

2018 ◽  
Author(s):  
Francesco Romeo ◽  
Antonio Di Bartolomeo
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Scattering Theory ◽  
Chemical Vapor ◽  
Transmission Probability ◽  
Industrial Applications ◽  
Large Area ◽  
Current Conservation ◽  
Long Wavelength ◽  
Boundary Properties

The implementation of graphene-based electronics requires fabrication processes able to cover large device areas since exfoliation method is not compatible with industrial applications. Chemical vapor deposition of large-area graphene represents a suitable solution having the important drawback of producing polycrystalline graphene with formation of grain boundaries, which are responsible for limitation of the device performance. With these motivations, we formulate a theoretical model of graphene grain boundary by generalizing the graphene Dirac Hamiltonian model. The model only includes the long-wavelength regime of the particle transport, which provides the main contribution to the device conductance. Using symmetry-based arguments deduced from the current conservation law, we derive unconventional boundary conditions characterizing the grain boundary physics and analyze their implications on the transport properties of the system. Angle resolved quantities, such as the transmission probability, are studied within the scattering matrix approach. The conditions for the existence of preferential transmission directions are studied in relation with the grain boundary properties. The proposed theory provides a phenomenological model to study grain boundary physics within the scattering approach and represents per se an important enrichment of the scattering theory of graphene. Moreover, the outcomes of the theory can contribute in understanding and limiting detrimental effects of graphene grain boundaries also providing a benchmark for more elaborated techniques.

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