scholarly journals How heteroepitaxy occurs on strontium titanate

2019 ◽  
Vol 5 (4) ◽  
pp. eaav0764 ◽  
Author(s):  
Seyoung Cook ◽  
Kendra Letchworth-Weaver ◽  
I-Cheng Tung ◽  
Tassie K. Andersen ◽  
Hawoong Hong ◽  
...  
Keyword(s):  
Critical Role ◽  
Substrate Material ◽  
Layer Growth ◽  
Perovskite Oxide ◽  
Layer By Layer ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Active ◽  
Oxide Substrate

In traditional models of heteroepitaxy, the substrate serves mainly as a crystalline template for the thin-film lattice, dictating the initial roughness of the film and the degree of coherent strain. Here, performing in situ surface x-ray diffraction during the heteroepitaxial growth of LaTiO3 on SrTiO3 (001), we find that a TiO2 adlayer composed of the (13×13)R33.7° and (2×2)R45.0° reconstructions is a highly active participant in the growth process, continually diffusing to the surface throughout deposition. The effects of the TiO2 adlayer on layer-by-layer growth are investigated using different deposition sequences and anomalous x-ray scattering, both of which permit detailed insight into the dynamic layer rearrangements that take place. Our work challenges commonly held assumptions regarding growth on TiO2-terminated SrTiO3 (001) and demonstrates the critical role of excess TiO2 surface stoichiometry on the initial stages of heteroepitaxial growth on this important perovskite oxide substrate material.

Growth of CaFeOX/LaFeO3 Superlattice on SrTiO3(100) Substrates

2011 ◽  
Vol 1292 ◽  
Author(s):  
Nobuyuki Iwata ◽  
Mark Huijben ◽  
Guus Rijnders ◽  
Hiroshi Yamamoto ◽  
Dave H. A. Blank
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Layer Growth ◽  
Laser Deposition ◽  
Growth Mode ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
X Ray

ABSTRACTThe CaFeOX(CFO) and LaFeO3(LFO) thin films as well as superlattices were fabricated on SrTiO3(100) substrates by pulsed laser deposition (PLD) method. The tetragonal LFO film grew with layer-by-layer growth mode until approximately 40 layers. In the case of CFO, initial three layers showed layer-by-layer growth, and afterward the growth mode was transferred to two layers-by-two layers (TLTL) growth mode. The RHEED oscillation was observed until the end of the growth, approximately 50nm. Orthorhombic twin CaFeO2.5 (CFO2.5) structure was obtained. However, it is expected that the initial three CFO layers are CaFeO3 (CFO3) with the valence of Fe4+. The CFO and LFO superlattice showed a step-terraces surface, and the superlattice satellite peaks in a 2θ-θ and reciprocal space mapping (RSM) x-ray diffraction (XRD) measurements, indicating that the clear interfaces were fabricated.

A SURFACE X-RAY DIFFRACTION STUDY OF THE GROWTH OF ULTRATHIN LAYERS OF Fe ON Cu(001)

1994 ◽  
Vol 01 (04) ◽  
pp. 631-634 ◽  
Author(s):  
M.A. JAMES ◽  
C. NORRIS ◽  
C.L. NICKLIN ◽  
R.G. VAN SILFHOUT ◽  
P.B. HOWES ◽  
...  
Keyword(s):  
Layer Growth ◽  
Detailed Knowledge ◽  
Exact Nature ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Iron Films ◽  
X Ray ◽  
Diffusion Limited ◽  
Ultrathin Layers ◽  
Fcc Phase

Although it is well known that the γ (fcc) phase of Fe can be stabilised on Cu(001) single crystal substrates, there is still considerable disagreement about the exact nature of the growth mode and the structures that evolve with increasing film thickness. A detailed knowledge of the structure and morphology is essential for a complete understanding of the magnetic properties of ultrathin iron films. Surface X-ray diffraction measurements, recorded in real time during deposition of Fe deposition on Cu(001), are presented. At room temperature, well-defined layer-by-layer growth, with no significant agglomeration of iron, was observed. The specular intensity of the X-ray beam varied parabolically with coverage, as predicted by kinematical theory. Intensity oscillations were observed up to 15 Fe monolayers, at which coverage relaxation to the α (bcc) phase was confirmed. At 85 K the growth is diffusion limited.

Growth twins in Bi2Ca1Sr2Cu2O8 superconductor single crystals

1990 ◽  
Vol 5 (5) ◽  
pp. 909-912 ◽  
Author(s):  
P. D. Han ◽  
A. Asthana ◽  
Z. Xu ◽  
D. A. Payne
Keyword(s):  
Electron Microscopy ◽  
Crystal Growth ◽  
Large Scale ◽  
Layer Growth ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Growth Morphology ◽  
X Ray ◽  
Twin Formation ◽  
First Time

Large-scale twin structures in single crystal Bi2Ca1Sr2Cu2O8 (2122) are reported for the first time. Symmetrical 90° (i.e., a-b) twins with a [110] type twin boundary were observed. A characteristic layer-growth morphology and jagged twin walls suggest that twin formation occurred layer by layer during crystal growth; i.e., the twins were growth twins. Hot-stage optical microscopy, x-ray diffraction, and electron microscopy results are discussed with reference to twin morphology.

EVALUATION OF Sr2YSbO6 AS A NEW SUBSTRATE FOR YBa2Cu3O7-δ SUPERCONDUCTOR THIN FILMS

2004 ◽  
Vol 18 (19n20) ◽  
pp. 1035-1042 ◽  
Author(s):  
O. ORTIZ DIAZ ◽  
J. ROA-ROJAS ◽  
D. A. LANDÍNEZ TÉLLEZ ◽  
J. ALBINO AGUIAR
Keyword(s):  
Lattice Mismatch ◽  
Magnetic Measurements ◽  
Chemical Interaction ◽  
Substrate Material ◽  
Perovskite Oxide ◽  
Structure Characteristic ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns

A complex perovskite oxide Sr 2 YSbO 6 has been synthesized by solid-state reaction. X-ray diffraction (XRD) pattern reveals that Sr 2 YSbO 6 has an ordered complex cubic structure characteristic of A 2 BB ' O 6 crystalline structure with lattice constant a=8.2561 Å which has a fairly good lattice matching (lattice mismatch of the order of 8%) with YBa 2 Cu 3 O 7-δ. Energy dispersive X-ray (EDX) analysis shows that Sr 2 YSbO 6 is free of impurity traces. The chemical stability of Sr 2 YSbO 6 with YBa 2 Cu 3 O 7-δ superconducting has been studied by X-ray diffraction and magnetic measurements on Sr 2 YSbO 6– YBa 2 Cu 3 O 7-δ composites. XRD patterns of the composite show that all the XRD peaks could be indexed for either Sr 2 YSbO 6 or YBa 2 Cu 3 O 7-δ with no extra peak detectable. This implies that YBa 2 Cu 3 O 7-δ and Sr 2 YSbO 6 remain as two different separate phases in the composite with no chemical interaction. Magnetic measurements show that superconducting transition temperature of pure YBa 2 Cu 3 O 7-δ and Sr 2 YSbO 6– YBa 2 Cu 3 O 7-δ composites is 90 K. These favorable characteristics of Sr 2 YSbO 6 show that it can be used as a potential substrate material for fabrication of YBa 2 Cu 3 O 7-δ superconducting films.

Layer-by-layer growth of GaAs() studied by in situ synchrotron X-ray diffraction

2003 ◽  
Vol 525 (1-3) ◽  
pp. 126-136 ◽  
Author(s):  
Wolfgang Braun ◽  
Bernd Jenichen ◽  
Vladimir M. Kaganer ◽  
Alexander G. Shtukenberg ◽  
Lutz Däweritz ◽  
...  
Keyword(s):  
Layer Growth ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
X Ray

Mbe Growth and Thermoelectric Properties OF Bi2Te3 Thin Films

1998 ◽  
Vol 545 ◽  
Author(s):  
Sunglae Cho ◽  
Yunki Kim ◽  
Antonio DiVenere ◽  
George K. L. Wong ◽  
Jerry R. Meyer ◽  
...  
Keyword(s):  
Thin Films ◽  
Antisite Defect ◽  
High Energy ◽  
Layer Growth ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
X Ray ◽  
Crystal Bulk

AbstractWe have grown high quality Bi2Te3 thin films on CdTe(111)B substrates using MBE. Structural properties have been investigated using in-situ reflection high-energy electron diffraction (RHEED) and θ-2θ X-ray diffraction analysis. They show that Bi2Te3films on CdTe(111) grow along the (00.l) in the hexagonal cell with a layer-by-layer growth mode, resulting in a smooth surface, and an X-ray Bragg peak FWHM of 0.2°. The thermopower and electrical conductivity of the stoichiometric Bi2Te3 films were ∼200 μV/K and 103(Ωcm)−1, respectively, comparable to the single crystal bulk values. We have observed the antisite defect effect in Te-rich Bi2Te3films: excess Te occupies Bi lattice sites and behaves as an n-type dopant. Crystallinity and transport properties are strongly affected by non-stoichiometry.

Chemical and Electrochemical Heteroepitaxial Growth of Chalcogenide Semiconductors from Solutions

1996 ◽  
Vol 451 ◽  
Author(s):  
D. Lincot ◽  
M. J. Furlong ◽  
M. Froment ◽  
R. Cortes ◽  
M. C. Bernard
Keyword(s):  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Basic Principles ◽  
Lattice Match ◽  
X Ray ◽  
Chalcogenide Semiconductors ◽  
Influence Of Temperature On ◽  
Deposition Processes ◽  
A Site ◽  
Site Selective

ABSTRACTChalcogenide semiconductors have been deposited epitaxially from aqueous solutions either chemically or electrochemically at growth rates of up to 0.7 μmhr−1. After recalling the basic principles of these deposition processes, results are presented concerning chemically deposited CdS on InP, GaP and CuInSe2 substrates, electrodeposited CdTe on InP, and CdSAnP heterostructures. Characterisation of these structures by RHEED, TEM, HRTEM, and glazing angle X ray diffraction allows to analyse the effects of substrate orientation, polarity, lattice match plus the influence of temperature on epitaxial growth. These results are discussed in terms of self organisation and a site selective growth mechanisms due to the free enegy of formation of each compound.

scholarly journals Metal(II) Coordination Polymers from Tetracarboxylate Linkers: Synthesis, Structures, and Catalytic Cyanosilylation of Benzaldehydes

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 204
Author(s):  
Yu Li ◽  
Chumin Liang ◽  
Xunzhong Zou ◽  
Jinzhong Gu ◽  
Marina V. Kirillova ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Polycarboxylic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trimethylsilyl Cyanide ◽  
Effect Of Solvent ◽  
Highly Active ◽  
Solvent Type ◽  
Metal Organic ◽  
Chloride Salts

Three 2D coordination polymers, [Cu2(µ4-dpa)(bipy)2(H2O)]n∙6nH2O (1), [Mn2(µ6-dpa)(bipy)2]n (2), and [Zn2(µ4-dpa)(bipy)2(H2O)2]n·2nH2O (3), were prepared by a hydrothermal method using metal(II) chloride salts, 3-(2′,4′-dicarboxylphenoxy)phthalic acid (H4dpa) as a linker, as well as 2,2′-bipyridine (bipy) as a crystallization mediator. Compounds 1–3 were obtained as crystalline solids and fully characterized. The structures of 1–3 were established by single-crystal X-ray diffraction, revealing 2D metal-organic networks of sql, 3,6L66, and hcb topological types. Thermal stability and catalytic behavior of 1–3 were also studied. In particular, zinc(II) coordination polymer 3 functions as a highly active and recoverable heterogeneous catalyst in the mild cyanosilylation of benzaldehydes with trimethylsilyl cyanide to give cyanohydrin derivatives. The influence of various parameters was investigated, including a time of reaction, a loading of catalyst and its recycling, an effect of solvent type, and a substrate scope. As a result, up to 93% product yields were attained in a catalyst recoverable and reusable system when exploring 4-nitrobenzaldehyde as a model substrate. This study contributes to widening the types of multifunctional polycarboxylic acid linkers for the design of novel coordination polymers with notable applications in heterogeneous catalysis.

Preparation of β-PbO2 and β-PbO2-MnO2 Coating on Stainless Steel Substrate

2012 ◽  
Vol 490-495 ◽  
pp. 3486-3490
Author(s):  
Qiang Yu ◽  
Zhen Chen ◽  
Zhong Cheng Guo
Keyword(s):  
Stainless Steel ◽  
Mass Fraction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Substrate Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Type ◽  
Plating Solution ◽  
Element Mass Fraction

In order to prepare a new type of anode material, stainless steel was selected as substrate material. The β-PbO2 coating on stainless steel substrate was prepared under the appropriate plating solution, and the PbO2-MnO2 coating was prepared with thermal decomposition. The crystal structure was determined by X-ray diffraction; Surface morphology was test by Scanning Electron Microscopy; the energy spectrum was used to determine element mass-fraction and the ratio of atomic number of the coatings.

Metal-Controlled Assembly Tuning Coordination Polymers with Flexible 2-(1H-imidazole-1-yl)acetic Acid (Hima)

2006 ◽  
Vol 59 (9) ◽  
pp. 647 ◽  
Author(s):  
Yong-Tao Wang ◽  
Gui-Mei Tang ◽  
Da-Wei Qin
Keyword(s):  
Coordination Polymers ◽  
Weak Interactions ◽  
Critical Role ◽  
Three Dimensional ◽  
Supramolecular Network ◽  
Water Medium ◽  
New Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supramolecular Networks

Three new inorganic–organic coordination polymers based on a versatile linking unit 2-(1H-imidazole-1-yl)acetate (Hima) and divalent Mn(ii), Ni(ii), and Cu(ii) ions, exhibiting two kinds of two dimensionalities with different topological structures, have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of MnCl2·4H2O and Ni(NO3)2·6H2O with Hima yielded neutral two-dimensional (2D) coordination polymers [M(ima)2]n, M = Mn(ii) 1, and Ni(ii) 2 with isostructural 2D coordination polymers possessing (3,6) topology structures, which further stack into three-dimensional (3D) supramolecular networks through C–H···O weak interactions. However, when Cu(NO3)2·4H2O was used, a neutral 2D coordination polymer [Cu(ima)2]n 3 consisting of rhombus units was generated, which showed a 3D supramolecular network through C–H···O weak interactions. Among these polymers, the building block ima anion exhibits different coordination modes. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal ions, plays a critical role in construction of these novel coordination polymers. Spectral and thermal properties of these new materials have also been investigated.

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