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

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.

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

MRS Proceedings ◽

10.1557/opl.2011.245 ◽

2011 ◽

Vol 1292 ◽

Cited By ~ 3

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.

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

Surface Review and Letters ◽

10.1142/s0218625x94000825 ◽

1994 ◽

Vol 01 (04) ◽

pp. 631-634 ◽

Cited By ~ 1

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.

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A compact UHV X-ray diffractometer for studying surfaces and interfaces

Journal of Synchrotron Radiation ◽

10.1107/s0909049597014489 ◽

1998 ◽

Vol 5 (3) ◽

pp. 887-889

Author(s):

Yoshikazu Fujii ◽

Takeshi Nakamura ◽

Mutsumi Kai ◽

Kentaroh Yoshida

Keyword(s):

High Vacuum ◽

Layer Growth ◽

Ultra High Vacuum ◽

Layer By Layer ◽

Crystal Surfaces ◽

X Ray ◽

Surfaces And Interfaces ◽

Optical Table ◽

Specimen Orientation

A compact ultra-high-vacuum (UHV) X-ray diffractometer for surface glancing X-ray scattering has been constructed. All the equipment, including a rotating-anode source of 18 kW and a UHV specimen chamber, is arranged on one optical table of dimensions 70 × 90 cm. The specimen chamber is 14 cm in diameter and 20 cm high and can be evacuated up to 3 × 10−8 Pa. It is equipped with two Be windows of thicknesses 0.2 and 0.4 mm. Specimen orientation in the vacuum is controlled from the outside. The specimen can be heated up to 773 K. The chamber has two evaporation cells and can be used for in situ observations of growing crystal surfaces. Using this instrument, we observed a mechanically polished Ag surface and successfully made an in situ observation of the layer-by-layer growth of a PbSe(111) surface. The instrument will be useful for preliminary experiments using laboratory sources, prior to final measurements at synchrotron radiation facilities.

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A MODEL OF STRUCTURAL DISORDER IN (Ba2Cu2O4+x)/(CaCuO2)n SUPERLATTICES

International Journal of Modern Physics B ◽

10.1142/s021797920000282x ◽

2000 ◽

Vol 14 (25n27) ◽

pp. 2719-2724

Author(s):

G. PASQUINI ◽

G. BALESTRINO ◽

S. LAVANGA ◽

P. G. MEDAGLIA ◽

G. PETROCELLI ◽

...

Keyword(s):

Structural Disorder ◽

Layer Growth ◽

Internal Stresses ◽

Layer By Layer ◽

Mixed Composition ◽

X Ray ◽

Order Of Magnitude ◽

Random Disorder ◽

Kinematical Approach

The structural disorder in ( Ba 2 Cu 2 O 4+x )/( CaCuO 2) n superlattices with ultrathin individual layers was investigated. Numerical simulations of x-ray spectra were carried out following a kinematical approach in a simplified model structure. The model assumes a two-dimensional layer by layer growth in which mixed composition layers can be corrugated to adjust the internal stresses due to the large mismatch between the constituent oxides. An additional random disorder is added to take into account the experimental dispersion in the amount of material deposited in each iteration. The model was successfully used to simulate x-ray spectra for samples with non integer n ranging from 2 to 16, grown in optimal conditions to obtain a superconducting behavior. The same model was used to simulate spectra of samples grown at lower pressures monitored with in-situ RHEED diagnostic. In this case, random disorder results more than one order of magnitude smaller.

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Preparation of (111)-Oriented Pt Electrode Films with Quasi-Monocrystal Properties on MgO/TiN Buffered Si(100) by PLD

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.823 ◽

2007 ◽

Vol 280-283 ◽

pp. 823-826 ◽

Cited By ~ 1

Author(s):

Tong Lai Chen ◽

Xiao Min Li

Keyword(s):

High Energy ◽

Layer Growth ◽

Atomic Scale ◽

Layer By Layer ◽

X Ray Diffraction ◽

Pt Electrode ◽

Force Microscopy ◽

Atomic Force

Atomic-scale smooth Pt electrode films have been deposited on MgO/TiN buffered Si (100) by the pulsed laser deposition (PLD) technique. The whole growth process of the multilayer films was monitored by using in-situ reflection high energy electron diffraction (RHEED) apparatus. The Pt/MgO/TiN/Si(100) stacked structure was also characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The HREED observations show that the growth mode of the Pt electrode film is 2D layer-by-layer growth. It is found that the (111)-oriented Pt electrode film has a crystallinity comparable to that of monocrystals. The achievement of the quasi-single-crystal Pt electrode film with an atomic-scale smooth surface is ascribed to the improved crystalline quality of the MgO film.

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Growth twins in Bi2Ca1Sr2Cu2O8 superconductor single crystals

Journal of Materials Research ◽

10.1557/jmr.1990.0909 ◽

1990 ◽

Vol 5 (5) ◽

pp. 909-912 ◽

Cited By ~ 7

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.

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Kinetic Control of CaF2 on Si(111) Growth Morphology

MRS Proceedings ◽

10.1557/proc-312-207 ◽

1993 ◽

Vol 312 ◽

Author(s):

J. D. Denlinger ◽

Eli Rotenberg ◽

U. Hessingert ◽

M. Leskovar ◽

Marjorie A. Olmstead

Keyword(s):

Photoelectron Spectroscopy ◽

Molecular Beam ◽

Layer Growth ◽

Layer By Layer ◽

X Ray ◽

Photoelectron Diffraction ◽

Triple Layer ◽

Growth Modes ◽

Level Shifts

AbstractThin (0.5 to 8 triple layer) CaF2 on Si(111) films were grown using molecular beam epitaxy (MBE) and characterized using an in situ combination of x-ray photoelectron spectroscopy (XPS) and componentresolved x-ray photoelectron diffraction (XPD). We identified surface, bulk-like, and interface F and Ca core-level shifts and used the XPS shifts and XPD modulations to identify the growth modes as a function of the kinetic parameters of CaF2 flux and Si temperature. We identify 3 distinct regimes: (i) for high temperatures and flux we find a complete reacted F-Ca-Si layer, overlaid by 2 layer high islands which coalesce, followed by layer-by-layer growth, (ii) for high temperature and low flux, we find the reacted F-Ca-Si layer to be partially covered with thick islands, and (iii) for low temperatures we find an incompletely occupied F-Ca-Si layer followed by layer-by-layer growth. In all cases we find the buried interface to be structurally identical to the unburied F-Ca-Si layer

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Combinatorial Molecular Layer Epitaxy of Hf Based Phosphor Oxides

MRS Proceedings ◽

10.1557/proc-700-s1.10 ◽

2001 ◽

Vol 700 ◽

Cited By ~ 1

Author(s):

N. Arai ◽

T. W. Kim ◽

H. Kubota ◽

Y. Matsumoto ◽

H. Koinuma

Keyword(s):

Molecular Layer ◽

High Energy ◽

Layer Growth ◽

Laser Deposition ◽

Layer By Layer ◽

High Energy Electron ◽

X Ray ◽

Substrate Interaction ◽

Film Substrate

AbstractA series of MHfO3: Tm (M =Ca, Sr and Ba) composition spread films and superlattices (SLs) were quickly fabricated on SrTiO3 (001) substrate in the molecular layer-by-layer growth using combinatorial pulsed laser deposition (PLD) under in-situ reflection high-energy electron diffraction (RHEED) monitoring. Crystal structures and luminescence properties of composition-spread and SLs were evaluated by the concurrent X-ray diffractometer and cathode luminescence (CL), respectively. CL properties of the films were found strongly dependent on their composition and stacking sequence. Possible effect of the stress due to the film-substrate interaction on the CL property is discussed.

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Amorphous Phase Formation in Solid State Reactions of Layered Nickel Zirconium Films

MRS Proceedings ◽

10.1557/proc-37-559 ◽

1984 ◽

Vol 37 ◽

Cited By ~ 5

Author(s):

Bruce M. Clemens ◽

Jeffrey C. Buchholz

Keyword(s):

Solid State ◽

Layer Thickness ◽

Amorphous Phase ◽

Amorphous Material ◽

Depth Profiling ◽

Layer Growth ◽

Solid State Reactions ◽

X Ray Diffraction ◽

X Ray

AbstractFormation of an amorphous zirconium-nickel phase by solid state reaction of a layered crystalline structure has been studied by in-situ resistivity, x-ray diffraction, and Auger depth profiling. The reaction was studied as a function of layer thickness and reaction temperature.Samples with a layer thickness of less than 4 atomic planes had x-ray diffraction spectra with one broad maximum characteristic of amorphous material. As the layer thickness increased, the maximum broadened and separated into two resolved peaks corresponding to crystalline nickel and zirconium. These structures were transformed to an amorphous nickel-zirconium alloy by an anneal at temperatures below the crystallization temperature of the amorphous phase. The reaction occured by a layer growth process, where the thickness of the layer evolved linearly with the square root of time.

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