Growth of Fluorite Solid Solution Crystals in the Ternary SrF2–BaF2–LaF3 System and Investigation of Their Properties

Crystallography Reports - A series of three-component isostructural fluorite crystals (Sr1–xBax)0.7La0.3F2.3 (sp. gr. $$Fm{\bar {3}}m$$ , 0 ≤ x ≤ 1), the compositions of...     

Growth of Pb on Si(3 3 5)–Au surface

The growth, crystallographic structure and electronic properties of ultrathin Pb films grown on a vicinal silicon surface are investigated with reflection high energy electron diffraction (RHEED) and specific resistivity measurement techniques. A Si(3 3 5) surface with a perfect distribution of monoatomic steps separated with (1 1 1) terraces induced by a submonolayer amount of Au is used as a substrate. In the early stage, Pb growth is anisotropic. Apparently, the presence of steps forces the growth of short crystalline Pb chains along the steps. The layer is amorphous in the perpendicular direction. With the increasing thickness, a phase transition takes place between 3 and 4 monolayers (ML) that makes crystalline order also across the terraces. A further increase in thickness causes the layer surface to repeat the substrate morphology. It consists of regularly distributed monoatomic steps and narrow (1 1 1) terraces.     

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 15. Concentration Dependence of the Defect Structure of As Grown Nonstoichiometric Phases Sr1 – xRxF2 + x (R = Sm,Gd)

Crystallography Reports - The defect structure of as grown single crystals Sr1 – xSmxF2 + x (x = 0.14, 0.26) and...     

High-Temperature Exciton Photoconductivity of Ge1 – xNdxS Crystals

Crystallography Reports - The spectral dependences of photoconductivity in a wide temperature range (T = 80–300 K) of layered GeS single crystals, both intentionally undoped and Nd-doped,...     

Growth and Morphological Study of Graded-Gap Si–Si1 – xGex–GaAs Structures

Crystallography Reports - Single-crystal films of Si1 – xGex (0 < x < 1) solid solution have been grown on Si substrates by liquid-phase epitaxy, and a...     

Structural Features of ZnxMg1 – xWO4 Mixed Crystals

Crystallography Reports - The structural features of a series of ZnxMg1–xWO4 mixed crystals (x = 0, 0.26, 0.41, 0.68, or 1) have been investigated using X-ray diffraction analysis and Raman...     

Epitaxial lateral overgrowth of non-polar GaN(1 1̄ 0 0) on Si(1 1 2) patterned substrates by MOCVD

m-Plane GaN was grown selectively by metal–organic chemical vapor deposition (MOCVD) on patterned Si(1 1 2) substrates, where grooves aligned parallel to the Si〈1 1 0〉 direction were formed by anisotropic wet etching to expose the vertical Si{1 1 1} facets for growth initiation. The effect of growth conditions (substrate temperature, chamber pressure, and ammonia and trimethylgallium flow rates) on the growth habits of GaN was studied with the aim of achieving coalesced m-plane GaN films. The epitaxial relationship was found to be GaN(1 1? 0 0) || Si(1 1 2), GaN[0 0 0 1] || Si[1 1 –1], GaN[1? 1? 2 0] || Si[1 1? 0]. Among all growth parameters, the ammonia flow rate was revealed to be the critical factor determining the growth habits of GaN. The distribution of extended defects, such as stacking faults and dislocations, in the selectively grown GaN were studied by transmission electron microscopy in combination with spatially resolved cathodoluminescence and scanning electron microscopy. Basal-plane stacking faults were found in the nitrogen-wing regions of the laterally overgrown GaN, while gallium-wings were almost free of extended defects, except for the regions near the GaN/Si{1 1 1} vertical sidewall interface, where high dislocation density was observed.     

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 14: Concentration Dependence of the Defect Structure of Nonstoichiometric Phases Sr1 – xNdxF2 + x As Grown (x = 0.10, 0.25, 0.40, 0.50)

Crystallography Reports - The defect structure of as grown Sr1 – xNdxF2 + x (x = 0.10–0.50) crystals grown from a melt by...     

Erratum to: “Concentration Dependences of the Lattice Parameter and Density of Ca1–xSrxF2 (0 ≤ x ≤ 1) Solid Solution Crystals”

Crystallography Reports - Reference no. 1 should read as follows: J. H. Burnett, Z. H. Levine, and E. L. Shirley, U.S. Patent No. 7163649 (2007). Reference no. 3 should read as follows: R. Yu....     

Influence of Temperature on the Defect Structure of the Fluorite Sr1 – xLaxF2 + x (x = 0.11–0.33) Single Crystals

Crystallography Reports - X-ray diffraction data on the Sr1 – xLaxF2 + x (x = 0.11, 0.24, 0.32, 0.33) single crystals with different thermal histories...     

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 13: Crystal Structure of SrF2 and Concentration Dependence of the Defect Structure of Nonstoichiometric Phase Sr1 – xLaxF2 + x As Grown (x = 0.11, 0.20, 0.32, 0.37, 0.47)

Crystallography Reports - The defect structure of as-grown SrF2 and nonstoichiometric phases Sr1 – xLaxF2 + x (x = 0.11, 0.20, 0.32, 0.37, 0.47) single...     

Role of interfacial crystallites in the crystallization of α-Fe2O3/α-Al2O3(0 0 0 1) thin films

In situ crystallization of α-Fe₂O₃/α-Al₂O₃(0 0 0 1) thin films was studied in real-time synchrotron X-ray scattering experiments. We find the coexistence of α-Fe₂O₃ (hexagonal) and Fe₃O₄ (cubic) interfacial crystallites (∼50-Å-thick), well aligned [0.02° full-width at half-maximum (FWHM)] to the α-Al₂O₃[0 0 0 1] direction, in the sputter-grown amorphous films. As the annealing temperature increases up to 750°C, the cubic stacking of the Fe₃O₄ crystallites gradually changes to the hexagonal α-Fe₂O₃ stacking, together with the growth of the well-aligned (WA) (0.02° FWHM) grains from the α-Fe₂O₃ crystallites. In the meanwhile, heterogeneous nucleation starts to occur on the substrate at ∼600°C, resulting in the formation of misaligned (1.39° FWHM) α-Fe₂O₃ grains. Our study reveals that the interfacial crystallites act as a template for the growth of the WA α-Fe₂O₃ grains.     

Comparative Analysis of the Methods for Obtaining Superconducting Fe1 + ySexTe1 – x Single Crystals

Crystallography Reports - The Fe1 + ySexTe1 – x single crystals grown by the KCl flux and Bridgman methods have been compared using the same investigation...     

Study of the Fracture Toughness of K2NixCo(1 – x)(SO4)2 · 6H2O Crystals in Dependence of the Growth Direction and Rate

Crystallography Reports - K2Ni(SO4)2 · 6H2O (KNSH), K2Co(SO4)2 · 6H2O (KCSH), and K2NixCo(1 – x)(SO4)2 · 6H2O (KCNSH) crystals have been grown by traditional...     

Mössbauer Study of the Effect of Cation Substitutions on the Magnetic Phase Transitions in BiFe1 – xCrxO3 and (1 – x)BiFeO3–xPbFe0.5Sb0.5O3 Solid Solutions

Crystallography Reports - The concentration dependences of the magnetic phase transition temperature TN, determined based on the changes in Mössbauer spectra, were investigated for a BiFeO3...     

Study of the Axial Distribution of Components of Sr1 − xTbxF2 + x Solid Solution Crystals during Their Directional Crystallization from Melt

Crystallography Reports - Crystals of fluorite solid solution Sr1 − xTbxF2 + x have been grown by the Bridgman technique from melts with the initial...     

Growth and characterization of lead-free Ba(1−x)CaxTi(1−y)ZryO3 single crystal

A lead-free Ba_(1?x)Ca_xTi_(1?y)Zr_yO₃ (BCZT) single crystal (x=0.08, y=0.26) was grown by the Czochralski (CZ) method in a mixed flux of TiO₂ and ZrO₂. The composition of as-grown BCZT was analyzed by electron probe micro-analysis. The structure, dielectric properties and phase transition were investigated at different temperatures. The X-ray diffraction results confirmed that the structure of the as-grown BCZT crystal was cubic both at 25 °C and 500 °C. The temperature dependence of the dielectric constant and Raman spectra characterization revealed that there was a phase transition from cubic to tetragonal, which happened between 200 K and 250 K. With increasing frequency, the Curie temperature shifted towards high temperature.     

MOCVD growth and optical properties of non-polar (1 1–2 0) a-plane GaN on (1 0–1 2) r-plane sapphire substrate

Non-polar a-plane GaN film with crystalline quality and anisotropy improvement is grown by use of high temperature AlN/AlGaN buffer, which is directly deposited on r-plane sapphire by pulse flows. Compared to the a-plane GaN grown on AlN buffer, X-ray rocking curve analysis reveals a remarkable reduction in the full width at half maximum, both on-axis and off-axis. Atomic force microscopy image exhibits a fully coalesced pit-free surface morphology with low root-mean-square roughness (∼1.5 nm). Photoluminescence is carried out on the a-plane GaN grown on r-plane sapphire. It is found that, at low temperature, the dominant emission at ∼3.42 eV is composed of two separate peaks with different characteristics, which provide explanations for the controversial attributions of this peak in previous studies.