Van der Waals Epitaxy of GaSe on GaAs(111)

1994 ◽  
Vol 340 ◽  
Author(s):  
L. E. Rumaner ◽  
F.S. Ohuchi
Keyword(s):  
Lattice Mismatch ◽  
Van Der Waals ◽  
Three Dimensional ◽  
Structured Materials ◽  
Lattice Matching ◽  
Molecular Beam Deposition ◽  
Crystal Films ◽  
Low Dimensional ◽  
Matching Constraints ◽  
Lattice Matched

ABSTRACTAlthough heteroepitaxy of lattice-matched and lattice-mismatched materials leading to artificially structured materials has resulted in impressive performance in various electronics devices, material combinations are usually limited by lattice matching constraints. A new concept for fabricating material systems using the atomically abrupt and low dimensional nature of layered materials, called van der Waals epitaxy (VDWE), has been developed. GaSe (Eg = 2.1 eV) has been deposited on the three dimensional surface of GaAs (111) using a molecular beam deposition system. GaSe was evaporated from a single Knudsen source, impinging on a heated substrate. Even with a lattice mismatch of 6% between the substrate and the growing film, good quality single crystal films were grown as determined by RHEED. The films have further been analyzed using a complementary combination of XPS and X-ray reflectivity.

Heteroepitaxy Between Lattice Mismatched Materials with Van Der Waals Interactions

1990 ◽  
Vol 198 ◽  
Author(s):  
Atsushi Koma
Keyword(s):  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Three Dimensional ◽  
Matching Condition ◽  
Van Der Waals Interactions ◽  
Heteroepitaxial Growth ◽  
Lattice Matching ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
Growth Methods

ABSTRACTThe lattice matching condition encountered usually in the heteroepitaxial growth has been proved to be relaxed drastically, if one uses the interface having van der Waals nature. Such interface can be realized on a cleaved face of a layered material or a quasi-one dimensional material and on a surface of a dangling-bond-terminated three dimensional material. Various kinds of heterostructures, which cannot be made by conventional growth methods, can be fabricated by using a variety of layered transition metal dichalcogenides, in which there exist superconducting, metallic, semiconducting or insulating layered materials. Moreover those heterostructures have been found to be grown on such an ordinary three-dimensional material as GaAs, if the dangling bonds on its surface are terminated by suitable atoms.

Temperature Dependent Orientational Epitaxy of C60 Films on Noble Metal (111) Surfaces; Au, Ag and Cu

1994 ◽  
Vol 359 ◽  
Author(s):  
A. Fartash
Keyword(s):  
Noble Metal ◽  
Lattice Mismatch ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Long Period ◽  
Molecular Beam Deposition ◽  
Unit Cells ◽  
Small Lattice ◽  
Substrate Temperatures ◽  
Lattice Matched

ABSTRACTHigh quality C60 films are grown on surfaces of (111) oriented noble metal substrates (i.e., Au, Ag, and Cu) by using a molecular beam deposition method. The structures of these films are compared with each other on substrates that are prepared to have similar in-plane mosaic widths (σ1.25*) as determined by their x-ray diffraction scans. The in-plane structures of these films are studied for substrate temperatures ranging from σ110 to 290°C. Although most materials grow in high symmetry small-lattice-mismatch in-plane orientations, C60 films (depending on their growth temperatures) grow in orientations that are poorly lattice matched with their Au(111) and Ag(111) substrates. In these orientations, C60 structures can be lattice matched only over large unit cells, forming “long-period ” structures. These “long-period ” structures coexist with “commensurate” structures that are almost perfectly lattice matched on twheitshe osur bpsrterdaotems.i naOten Au(111) substrates, a structural transition is observed between two distinct long-period structures (at Tc, σ150 °C). Although Au and Ag have similar lattice spacings, this transition is absent on Ag(111) substrates. The question of orientational epitaxy for C60 layers is examined in the context of several well-known systems in condensed matter physics.

scholarly journals Superconducting contact and quantum interference between two-dimensional van der Waals and three-dimensional conventional superconductors

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Michael R. Sinko ◽  
Sergio C. de la Barrera ◽  
Olivia Lanes ◽  
Kenji Watanabe ◽  
Takashi Taniguchi ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Van Der Waals ◽  
Three Dimensional ◽  
Two Dimensional

Effect Of Phosphorus On Ge/Si(001) Island Formation

2002 ◽  
Vol 737 ◽  
Author(s):  
Theodore I. Kamins ◽  
Gilberto Medeiros-Ribeiro ◽  
Douglas A. A. Ohlberg ◽  
R. Stanley Williams
Keyword(s):  
Deposition Rate ◽  
Strain Energy ◽  
Competitive Adsorption ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Deposition Process ◽  
Thin Layers ◽  
Island Size ◽  
Partial Pressures ◽  
Intermediate Size

ABSTRACTWhen Ge is deposited epitaxially on Si, the strain energy from the lattice mismatch causes the Ge in layers thicker than about four monolayers to form distinctive, three-dimensional islands. The shape of the islands is determined by the energies of the surface facets, facet edges, and interfaces. When phosphorus is added during the deposition, the surface energies change, modifying the island shapes and sizes, as well as the deposition process. When phosphine is introduced to the germane/hydrogen ambient during Ge deposition, the deposition rate decreases because of competitive adsorption. The steady-state deposition rate is not reached for thin layers. The deposited, doped layers contain three different island shapes, as do undoped layers; however, the island size for each shape is smaller for the doped layers than for the corresponding undoped layers. The intermediate-size islands are the most significant; the intermediate-size doped islands are of the same family as the undoped, multifaceted “dome” structures, but are considerably smaller. The largest doped islands appear to be related to the defective “superdomes” discussed for undoped islands. The distribution between the different island shapes depends on the phosphine partial pressure. At higher partial pressures, the smaller structures are absent. Phosphorus appears to act as a mild surfactant, suppressing small islands.

scholarly journals First-Principles Study on Graphene/Mg2Si Interface of Selective Laser Melting Graphene/Aluminum Matrix Composites

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 941
Author(s):  
Zhanyong Zhao ◽  
Shijie Chang ◽  
Jie Wang ◽  
Peikang Bai ◽  
Wenbo Du ◽  
...  
Keyword(s):  
Interfacial Energy ◽  
First Principles ◽  
Lattice Mismatch ◽  
Van Der Waals ◽  
Aluminum Matrix ◽  
Van Der Waals Force ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Charge Density Difference ◽  
Interface Charge

The bonding strength of a Gr/Mg2Si interface was calculated by first principles. Graphene can form a stable, completely coherent interface with Mg2Si. When the (0001) Gr/(001) Mg2Si crystal plane is combined, the mismatch degree is 5.394%, which conforms to the two-dimensional lattice mismatch theory. At the interface between Gr/Mg2Si, chemical bonds were not formed, there was only a strong van der Waals force; the interfaces composed of three low index surfaces (001), (011) and (111) of Mg2Si and Gr (0001) have smaller interfacial adhesion work and larger interfacial energy, the interfacial energy of Gr/Mg2Si is much larger than that of α-Al/Al melt and Gr/Al interfacial (0.15 J/m2, 0.16 J/m2), and the interface distance of a stable interface is larger than the bond length of a chemical bond. The interface charge density difference diagram and density of states curve show that there is only strong van der Waals force in a Gr/Mg2Si interface. Therefore, when the Gr/AlSi10Mg composite is stressed and deformed, the Gr/Mg2Si interface in the composite is easy to separate and become the crack propagation source. The Gr/Mg2Si interface should be avoided in the preparation of Gr/AlSi10Mg composite.

scholarly journals Three-Dimensional Macroscopic Assemblies of Low-Dimensional Carbon Nitrides for Enhanced Hydrogen Evolution

2013 ◽  
Vol 125 (42) ◽  
pp. 11289-11293 ◽  
Author(s):  
Young-Si Jun ◽  
Jihee Park ◽  
Sun Uk Lee ◽  
Arne Thomas ◽  
Won Hi Hong ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Three Dimensional ◽  
Carbon Nitrides ◽  
Low Dimensional

Thermal Strain Study of Almost Lattice-Matched Epitaxial InuGa1-uAs1-vP1-v Films on InP(100) Substrates

1989 ◽  
Vol 160 ◽  
Author(s):  
G. Bai ◽  
M-A. Nicolet ◽  
S.-J. Kim ◽  
R.G. Sobers ◽  
J.W. Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Epitaxial Film ◽  
Lattice Mismatch ◽  
Thermal Strain ◽  
Growth Direction ◽  
Epitaxial Films ◽  
Double Crystal ◽  
X Ray ◽  
Lattice Matched ◽  
Coherent Interfaces

AbstractSingle layers of ~ 0.5µm thick InuGa1-uAs1-vPv (0.52 < u < 0.63 and 0.03 < v < 0.16) were grown epitaxially on InP(100) substrates by liquid phase epitaxy at ~ 630°C. The compositions of the films were chosen to yield a constant banndgap of ~ 0.8 eV (λ = 1.55 µm) at room temperature. The lattice mismatch at room temperature between the epitaxial film and the substrate varies from - 4 × 10-3 to + 4 × 10-3. The strain in the films was characterized in air by x-ray double crystal diffractometry with a controllable heating stage from 23°C to ~ 700°C. All the samples have an almost coherent interfaces from 23°C to about ~ 330°C with the lattice mismatch accomodated mainly by the tetragonal distortion of the epitaxial films. In this temperature range, the x-ray strain in the growth direction increases linearly with temperature at a rate of (2.0 ± 0.4) × 10-6/°C and the strain state of the films is reversible. Once the samples are heated above ~ 300°C, a significant irreversible deterioration of the epitaxial films sets in.

A Low-Dimensional Dissimilarity Analysis of Unilateral and Bilateral Stroke-Impacted Hand Trajectories

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Jay Ryan U. Roldan ◽  
Dejan Milutinović ◽  
Zhi Li ◽  
Jacob Rosen
Keyword(s):  
Multidimensional Scaling ◽  
Healthy Subject ◽  
Motion Capture ◽  
Early Phase ◽  
Three Dimensional ◽  
High Rate ◽  
Motion Capture System ◽  
Trajectory Data ◽  
The Difference ◽  
Low Dimensional

In this paper, we propose a quantitative approach based on identifying hand trajectory dissimilarities through the use of a multidimensional scaling (MDS) analysis. A high-rate motion capture system is used to gather three-dimensional (3D) trajectory data of healthy and stroke-impacted hemiparetic subjects. The mutual dissimilarity between any two trajectories is measured by the area between them. This area is used as a dissimilarity variable to create an MDS map. The map reveals a structure for measuring the difference and variability of individual trajectories and their groups. The results suggest that the recovery of hemiparetic subjects can be quantified by comparing the difference and variability of their individual MDS map points to the points from the cluster of healthy subject trajectories. Within the MDS map, we can identify fully recovered patients, those who are only functionally recovered, and those who are either in an early phase of, or are nonresponsive to the therapy.

Electronic Transport through Conical Nanosized GaAs Pillars

2015 ◽  
Vol 1735 ◽  
Author(s):  
Thorben Bartsch ◽  
Christian Heyn ◽  
Wolfgang Hansen
Keyword(s):  
Electronic Transport ◽  
Three Dimensional ◽  
Electronic States ◽  
Quantum Point Contacts ◽  
Point Contacts ◽  
Quantum Size ◽  
Current Voltage ◽  
Quantum Point ◽  
Current Voltage Characteristics ◽  
Lattice Matched

ABSTRACTWe study the electronic transport through epitaxial GaAs nanopillars that are only 16 nm long, with diameters of about 100 nm at the upper and 40 nm at the lower end. The pillars can be considered to be very short conical nanowires embedded in AlGaAs. They represent quantum point contacts between two perfectly lattice matched three-dimensional GaAs charge reservoirs. Distinctive asymmetries are found in the current-voltage characteristics. We associate them with the conical shape of the pillars. Although contact reservoirs and pillars are made from the same material, the transport through the pillars is dominated by tunneling across shallow barriers. This is explained by the quantum size effect on the electronic states within the pillars.

Low-dimensional lattices. VI. Voronoi reduction of three-dimensional lattices

1992 ◽  
Vol 436 (1896) ◽  
pp. 55-68 ◽  
Keyword(s):  
Simple Formula ◽  
Three Dimensional ◽  
Voronoi Cell ◽  
Dimensional Lattice ◽  
Usual Treatment ◽  
Low Dimensional

The aim of this paper is to describe how the Voronoi cell of a lattice changes as that lattice is continuously varied. The usual treatment is simplified by the introduction of new parameters called the vonorms and conorms of the lattice. The present paper deals with dimensions n ≼ 3; a sequel will treat four-dimensional lattices. An elegant algorithm is given for the Voronoi reduction of a three-dimensional lattice, leading to a new proof of Voronoi’s theorem that every lattice of dimension n ≼ 3 is of the first kind, and of Fedorov’s classification of the three-dimensional lattices into five types. There is a very simple formula for the determinant of a three-dimensional lattice in terms of its conorms.

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