The Role of Lattice Mismatch in Growth of Epitaxial Cubic Silicides on Silicon

1984 ◽  
Vol 37 ◽  
Author(s):  
R. A. Hamm ◽  
J. M. Vandenberg ◽  
J. M. Gibson ◽  
R. T. Tung
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Growth Direction ◽  
Subsequent Annealing ◽  
Misfit Dislocations ◽  
X Ray ◽  
Nickel Disilicide

AbstractThe lattice mismatch of single-crystal epitaxial nickel disilicide of orientation A and B on Si(111) has been measured in and out of the <111> growth direction using a four-circle X-ray diffractometer. In both directions the mismatch of the as-grown B-type film was found to be larger than for the A-type; after annealing at 800°C the mismatch of the A-type approached the value of the B-type, while the latter remained the same. This result suggests that the B-type NiSi2 film has relaxed more during growth than the A-type which can only be relieved by subsequent annealing. This difference in A- and B-type mismatch is correlated with TEM studies. The combined results provide evidence that the growth of either A or B orientation is strongly affected by the nature and density of the misfit dislocations.

scholarly journals Growth and Characterization of High-Quality GaN Nanowires on PZnO and PGaN by Thermal Evaporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
L. Shekari ◽  
H. Abu Hassan ◽  
S. M. Thahab ◽  
Z. Hassan
Keyword(s):  
Gallium Nitride ◽  
Thermal Evaporation ◽  
Lattice Mismatch ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gan Nanowires ◽  
Transmission Electron

In the current research, an easy and inexpensive method is used to synthesize highly crystalline gallium nitride (GaN) nanowires (NWs) on two different substrates [i.e., porous zinc oxide (PZnO) and porous gallium nitride (PGaN)] on Si (111) wafer by thermal evaporation without any catalyst. Microstructural studies by scanning electron microscopy and transmission electron microscope measurements reveal the role of the substrates in the nucleation and alignment of the GaN NWs. Further structural and optical characterizations were performed using high-resolution X-ray diffraction, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. Results indicate that the NWs have a single-crystal hexagonal GaN structure and growth direction in the (0001) plane. The quality and density of GaN NWs grown on different substrates are highly dependent on the lattice mismatch between the NWs and their substrates. Results indicate that NWs grown on PGaN have better quality and higher density compared to NWs on PZnO.

The scandium-rich indide Sc50Pt13.47In2.53

2020 ◽  
Vol 75 (6-7) ◽  
pp. 715-720 ◽  
Author(s):  
Nataliya L. Gulay ◽  
Jutta Kösters ◽  
Yaroslav M. Kalychak ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Intermetallic Phases ◽  
Subsequent Annealing ◽  
Induction Melting ◽  
X Ray

AbstractThe scandium-rich indide Sc50Pt13.47In2.53 was obtained by induction melting of the elements and subsequent annealing. The structure of Sc50Pt13.47In2.53 has been refined from single-crystal X-ray diffractometer data: Fm$\overline{3}$, a = 1774.61(3) pm, wR2 = 0.0443, 1047 F2 values and 35 variables. Sc50Pt13.47In2.53 is isopointal with the intermetallic phases Sc50Co12.5In3.5, Sc50Rh13.3In2.7, Sc50Ir13.6In2.4, Ag7+xMg26−x and Ga4.55Mg21.85Pd6.6 (Pearson code cF264 and Wyckoff sequence ih2fecba). Two of the eight crystallographic sites in the structure show mixed occupancies: M1 (≡Pt20.70In10.30) and M2 (≡Pt30.76In20.24). The structure contains four basic polyhedra: M2@Sc8 cubes, Pt1@Sc10 sphenocorona and slightly distorted M1@Sc12 and In3@Sc12 icosahedra. The polyhedra are condensed via common scandium corners and edges. The various Sc–Sc distances range from 302–334 pm and are indicative of substantial Sc–Sc bonding, stabilizing the Sc50Pt13.47In2.53 structure.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Time Dependence of γ/γ' Lattice Mismatch in Creep-Deformed Single Crystal Superalloy SC16 at 1173 K

2007 ◽  
Vol 539-543 ◽  
pp. 3059-3063 ◽  
Author(s):  
G. Schumacher ◽  
N. Darowski ◽  
I. Zizak ◽  
Hellmuth Klingelhöffer ◽  
W. Chen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Lattice Misfit ◽  
Peak Position ◽  
Single Crystal Superalloy ◽  
Tensile Creep ◽  
Full Width ◽  
X Ray Diffraction ◽  
X Ray ◽  
Time Period

The profiles of 001 and 002 reflections have been measured at 1173 K as a function of time by means of X-ray diffraction (XRD) on tensile-creep deformed specimens of single crystal superalloy SC16. Decrease in line width (full width at half maximum: FWHM) by about 7 % and increase in peak position by about 3x10-4 degrees was detected after 8.5x104 s. Broadening of the 002 peak profile indicated a more negative value of the lattice misfit after the same time period. The results are discussed in the context of the anisotropic arrangement of dislocations at the γ/γ’ interfaces during creep and their rearrangement during the thermal treatment at 1173 K.

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.

Crystallinity of YBa2Cu3O7−x single crystals grown by the pulling method

1996 ◽  
Vol 11 (4) ◽  
pp. 804-812 ◽  
Author(s):  
Y. Namikawa ◽  
M. Egami ◽  
S. Koyama ◽  
Y. Shiohara ◽  
H. Kutami
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Growth Direction ◽  
Annealed Sample ◽  
Seed Crystal ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Crystal Seed ◽  
Better Than

Large YBa2Cu3O7−x (Y123) single crystals (larger than 13 mm cubed) have been grown along the c-axis reproducibly by the modified pulling method. The crystallinity of Y123 single crystal was investigated by x-ray diffraction and x-ray topography. Crystals grown from an MgO single crystal seed had some low angle subgrain boundaries which tilted 0.1–0.8° from each other. These grain boundaries originated from the seed crystal, and the subgrains were extended along the growth direction from the seed crystal. Y123 single crystals with no marked subgrains in the whole area were obtained by using Y123 single subgrain crystal seeds. FWHM of the x-ray rocking curve for the crystal so produced was about 0.14°, which was much better than the spectrum consisting of several separated peaks obtained from the previous crystals. Tc onset of the annealed sample was about 93.6 K, and the transition width was about 0.9 K. The low angle subgrain boundaries did not seem to be effective pinning centers for the magnetic flux.

Structure Refinement of CePtSi and Hydrogenation Behavior of CePdGe, CePtSi and CePtGe

2007 ◽  
Vol 62 (4) ◽  
pp. 613-616 ◽  
Author(s):  
Wilfried Hermes ◽  
Ute Ch. Rodewald ◽  
Bernard Chevalier ◽  
Rainer Pötgena
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Subsequent Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydride Formation ◽  
Arc Melting ◽  
Cerium Compounds

The intermetallic cerium compounds CePdGe, CePtSi, and CePtGe were synthesized from the elements by arc-melting and subsequent annealing. The structure of CePtSi was refined from single crystal X-ray diffraction data: LaPtSi-type (ordered α-ThSi2 version), 141md, a = 419.6(1) and c = 1450.0(5) pm, wR2 = 0.0490, 362 F2 values and 16 variables. The Pt-Si distances within the three-dimensional [PtSi] network are 242 pm, indicating strong Pt-Si interactions. Hydrogenation of the three compounds at 623 K and 4 MPa H2 gave no indication for hydride formation.

scholarly journals The Role of Percent Volume Buried in the Characterization of Copper(I) Complexes for Lighting Purposes

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2647 ◽  
Author(s):  
Murat Alkan-Zambada ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Quantum Yields ◽  
X Ray ◽  
Photophysical Behavior

The usefulness of percent volume buried (%Vbur) as a readily quantifiable property is investigated with regard to [Cu(NN)(PP)]+ complexes of interest for lighting purposes. Photoluminescence quantum yields (PLQYs) and single crystal X-ray structures of 100 reported compounds were assembled, %Vbur of the ligand systems were calculated and analyzed for correlations. We found that increased shielding of the central Cu(I) cation relying on shared contributions of both (NN) and (PP) ligand systems led to increased PLQYs. These findings are of relevance for future characterizations of Cu(I)-based complexes and their photophysical behavior in the solid-state.

Structural properties of molecular beam epitaxy grown Ni/Pt superlattices

1997 ◽  
Vol 12 (1) ◽  
pp. 161-174 ◽  
Author(s):  
W. Staiger ◽  
A. Michel ◽  
V. Pierron-Bohnes ◽  
N. Hermann ◽  
M. C. Cadeville
Keyword(s):  
Molecular Beam ◽  
Growth Direction ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Superlattice Peak ◽  
Diffraction Peaks ◽  
Diffraction Patterns

We find that the [Ni3.2nmPt1.6nm] × 15 and [Ni3.2nmPt0.8nm] × 15 multilayers are semicoherent and display a columnar morphology. From both the period of the moir’e fringes and the positions of the diffraction peaks in electronic (plan-view and crosssection geometries) and x-ray diffraction patterns, one deduces that the nickel is relaxed (at least in the error bars of all our measurements), whereas the platinum remains slightly strained (≈−1%). The interfaces are sharp; no intermixing takes place giving rise to neat contrasts in transmission electron microscopy (TEM) and to high intensities of the superlattice peaks in the growth direction in both diffraction techniques. The relaxation of the interfacial misfit occurs partially through misfit dislocations, partially through the strain of platinum. A quasiperiodic twinning occurs at the interfaces, the stacking fault which forms the twin being the most often located at the interface Pt/Ni, i.e., when a Pt layer begins to grow on the Ni layer. The simulation of the θ/2θ superlattice peak intensities takes into account the columnar microstructure. It shows that the roughness is predominantly at medium scale with a fluctuation of about 12.5% for Ni layers and negligible for Pt layers.

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