Growth Mechanism and Opmization of MOD CeO2 Buffer Layers for TFA YBa2Cu3O7/CeO2 Multilayers

2005 ◽  
Vol 868 ◽  
Author(s):  
Felip Sandiumenge ◽  
Andrea Cavallaro ◽  
Mariona Coll ◽  
Jaume Gàzquez ◽  
Teresa Puig ◽  
...  
Keyword(s):  
Grain Growth ◽  
High Energy ◽  
Buffer Layers ◽  
Atmospheric Conditions ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Granular Microstructure

AbstractThe evolution from a partially oriented granular microstructure to a dense epitaxial one in CeO2 buffer layers deposited by metallorganic decomposition (MOD) on single crystal Y-stabilised ZrO2 (YSZ) substrates, has been investigated. CeO2 buffer layers were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), reflection high energy electron diffraction (RHEED), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Reducing atmospheric conditions inhibit grain growth resulting in a nanometric granular microstructure with a high concentration of C impurities decorating grain boundaries and porosity. Oxidation and elimination of C species promotes grain growth resulting in a dense epitaxial film, as well as stabilizes otherwise energetically prohibitive polar (001) planes. Trifluoracetate (TFA) derived MOD YBa2Cu3O7 (YBCO) films deposited on optimized CeO2 buffers exhibit a sharp interface while the undesired reaction giving BaCeO3 is minimized. Jc values of 1.5 MA/cm2 and 14 MA/cm2 at 77K and 5K, respectively, are achieved.

Study of Swift Heavy Ion Irradiation Induced Nanophases of TiO2

2013 ◽  
Vol 24 ◽  
pp. 133-139 ◽  
Author(s):  
Madhavi Thakurdesai ◽  
A. Mahadkar ◽  
Varsha Bhattacharyya
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
High Energy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Non Equilibrium

Ion beam irradiation is a unique non-equilibrium technique for phase formation and material modification. Localized rise in temperature and ultra fast (~1012 s) dissipations of impinging energy make it an attractive tool for nanostructure synthesize. Dense electronic excitation induced spatial and temporal confinement of high energy in a narrow dimension leads the system to a highly non-equilibrium state and the system then relaxes dynamically inducing nucleation of nanocrystals along the latent track. In the present investigation, amorphous thin films of TiO2 are irradiated by 100 MeV Ag ion beam. These irradiated thin films are characterized by Atomic Force Microscopy (AFM), Glancing Angle X-ray Diffraction (GAXRD), Transmission Electron Microscopy (TEM) and UV-VIS absorption spectroscopy. AFM and TEM studies indicate formation of circular nanoparticles of size 10±2 nm in a film irradiated at a fluence of 1×1012 ions.cm-2. Nanophase formation is also inferred from the blueshift observed in UV-VIS absorption band edge.

Investigation of ZnFe2O4 Nanoparticles Prepared by High Energy Milling

2009 ◽  
Author(s):  
S. S. Srinivasan ◽  
N. Kislov ◽  
Yu. Emirov ◽  
D. Y. Goswami ◽  
E. K. Stefanakos
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Energy Gap ◽  
Blue Shift ◽  
High Energy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coefficient Estimation ◽  
Transmission Electron

Nanoparticles of Zinc Ferrite (ZnFe2O4) prepared by both wet- and dry- high-energy ball milling (HEBM), have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), surface area and pore size distribution (BET) and wavelength-dependent diffuse reflectance and scattering turned into absorption coefficient estimation using the Kubelka-Munk theory. It was found that after 72 hours of HEBM, the particle size was decreased from 220 nm for the initial material to 16.5 nm and 9.4 nm for the wet- and dry-milled samples, respectively. The optical absorption analysis revealed that the energy gap is increased (blue shift) by 0.45 eV for wet-milled and decreased (“anomalous” red shift) by 0.15 eV for dry-milled samples of ZnFe2O4 as the particle size decreased.

scholarly journals The effect of periodic silane burst on the properties of GaN on Si (111) substrates

2004 ◽  
Vol 831 ◽  
Author(s):  
K. Y. Zang ◽  
S. J. Chua ◽  
C. V. Thompson ◽  
L. S. Wang ◽  
S. Tripathy ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Buffer Layers ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Gan On Si ◽  
Aln Buffer

ABSTRACTThe periodic silane burst technique was employed during metalorganic chemical vapor deposition of epitaxial GaN on AlN buffer layers grown on Si (111). Periodic silicon delta doping during growth of both the AlN and GaN layers led to growth of GaN films with decreased tensile stresses and decreased threading dislocation densities, as well as films with improved quality as indicated by x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. The possible mechanism of the reduction of tensile stress and the dislocation density is discussed in the paper.

High Quality Epitaxial Pt Films Grown on γ-Al2O3/Si (111) Substrates

2007 ◽  
Vol 124-126 ◽  
pp. 181-184
Author(s):  
Mikinori Ito ◽  
Kazuaki Sawada ◽  
Makoto Ishida
Keyword(s):  
Molecular Beam ◽  
Rf Magnetron Sputtering ◽  
High Energy ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pt Films

Epitaxial Pt films were grown on γ-Al2O3/Si (111) substrate by RF-magnetron sputtering. The γ-Al2O3 buffer layers were grown epitaxially using molecular beam epitaxy. The films were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and atomic force microscopy (AFM). The results of XRD showed that high-quality Pt films were obtained at around 560°C. In addition, the Pt films exhibited a very smooth surface with the root-mean-square (rms) surface roughness is about 0.4 nm.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

scholarly journals Dielectric Function of AlN Grown on Si (111) by MBE

1999 ◽  
Vol 572 ◽  
Author(s):  
Stefan Zollner ◽  
Atul Konkar ◽  
R. B. Gregory ◽  
S. R. Wilson ◽  
S. A. Nikishin ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Buffer Layers ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Growth Morphology ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth ◽  
Peak Widths

ABSTRACTWe measured the ellipsometric response from 0.7–5.4 eV of c-axis oriented AlN on Si (111) grown by molecular beam epitaxy. We determine the film thicknesses and find that for our AlN the refractive index is about 5–10% lower than in bulk AlN single crystals. Most likely, this discrepancy is due to a low film density (compared to bulk AlN), based on measurements using Rutherford backscattering. The films were also characterized using atomic force microscopy and x-ray diffraction to study the growth morphology. We find that AlN can be grown on Si (111) without buffer layers resulting in truely two-dimensional growth, low surface roughness, and relatively narrow x-ray peak widths.

Epitaxial BaTiO3 Thin Films on Different Substrates for Optical Waveguide Applications

1999 ◽  
Vol 597 ◽  
Author(s):  
M. Siegert ◽  
Judit G. Lisoni ◽  
C. H. Lei ◽  
A. Eckau ◽  
W. Zander ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Waveguides ◽  
Rutherford Backscattering Spectrometry ◽  
Optical Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Transmission Electron

AbstractIn the process of developing thin film electro-optical waveguides we investigated the influence of different substrates on the optical and structural properties of epitaxial BaTiO3 thin films. These films are grown by on-axis pulsed laser deposition (PLD) on MgO(100), MgAl2O4(100), SrTiO3(100) and MgO buffered A12O3(1102) substrates. The waveguide losses and the refractive indices were measured with a prism coupling setup. The optical data are correlated to the results of Rutherford backscattering spectrometry/ion channeling (RBS/C). X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). BaTiO3 films on MgO(100) substrates show planar waveguide losses of 3 dB/cm and ridge waveguide losses of 5 dB/cm at a wavelength of 633 nm.

scholarly journals All chemical YBa2Cu3O7 superconducting multilayers: Critical role of CeO2 cap layer flatness

2009 ◽  
Vol 24 (4) ◽  
pp. 1446-1455 ◽  
Author(s):  
M. Coll ◽  
J. Gàzquez ◽  
R. Huhne ◽  
B. Holzapfel ◽  
Y. Morilla ◽  
...  
Keyword(s):  
Critical Role ◽  
High Energy ◽  
Buffer Layers ◽  
Solution Deposition ◽  
Ybco Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Densities ◽  
Atomically Flat

New advances toward microstructural improvement of epitaxial CeO2 films grown by chemical solution deposition and their use as buffer layers for YBa2Cu3O7 (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr4+) or trivalent (Gd3+) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction, and a new methodology is also presented to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm−2 at 77 K.

Sign in / Sign up

Export Citation Format

Share Document