Extended layer-by-layer Madelung potential analysis of layered oxyhalide photocatalysts and other layered systems

2019 ◽  
Vol 7 (34) ◽  
pp. 19846-19851 ◽  
Author(s):  
Daichi Kato ◽  
Ryu Abe ◽  
Hiroshi Kageyama
Keyword(s):  
Layered Materials ◽  
Layer By Layer ◽  
Layered Systems ◽  
Potential Analysis ◽  
Madelung Potential

Extended layer-by-layer Madelung analysis was developed and applied to various layered materials to reveal the contribution of distant layers to Madelung site potential.

scholarly journals Layer-by-Layer Deposition of Organically Capped Quantum Dots

2006 ◽  
Vol 514-516 ◽  
pp. 1111-1115 ◽  
Author(s):  
Márcia C. Neves ◽  
Angela S. Pereira ◽  
Marco Peres ◽  
Andréi L. Kholkin ◽  
Teresa Monteiro ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Linear Increase ◽  
Layer By Layer ◽  
Layered Systems ◽  
Quantum Size ◽  
Layer Deposition ◽  
Cadmium Chalcogenide ◽  
Afm Analysis ◽  
Quartz Substrates ◽  
Light Absorbance

Cadmium chalcogenide quantum dots (QD’s) were synthesised using a single source approach while zinc oxide QD’s were obtained by a colloidal technique. In both situations the dots were surface capped with tri-octylphosphine oxide (TOPO) hence leading to nanodispersed systems in organic solvents such as toluene. The organically capped QD’s (CdSe, CdS and ZnO) were used as building-units to fabricate LbL (layer-by-layer) films on glass and quartz substrates. A linear increase in the visible light absorbance (due to the QD’s) with the number of deposited layers indicates that multi-layered systems have been fabricated. In order to investigate the effect of the LbL manipulation on the integrity of the QD’s, comparative studies on the optical properties of the starting QD’s and the nanostructured films have been performed. The observation of quantum size effects in both cases suggests minimal degradation of the QD’s though clustering had probably occurred, a point which was further confirmed by AFM analysis.

Layer-by-Layer Assembly and Spontaneous Flocculation of Oppositely Charged Oxide and Hydroxide Nanosheets into Inorganic Sandwich Layered Materials

2007 ◽  
Vol 129 (25) ◽  
pp. 8000-8007 ◽  
Author(s):  
Liang Li ◽  
Renzhi Ma ◽  
Yasuo Ebina ◽  
Katsutoshi Fukuda ◽  
Kazunori Takada ◽  
...  
Keyword(s):  
Layered Materials ◽  
Layer By Layer ◽  
Layer By Layer Assembly ◽  
Oppositely Charged ◽  
Layer Assembly

Functionally-oriented composite layered materials with martensitic transformations

2022 ◽  
pp. 1-9
Author(s):  
P O Rusinov ◽  
Zh M Blednova ◽  
G V Kurapov
Keyword(s):  
Thermomechanical Treatment ◽  
Structural Parameters ◽  
Martensitic Transformations ◽  
Ceramic Materials ◽  
Layered Materials ◽  
Economic Feasibility ◽  
Layer By Layer ◽  
Electron Microscopic ◽  
Composite Surface ◽  
High Entropy

The studies carried out show that the task of ensuring the reliability and expanding the functionality of products operating under multifactorial effects (temperature, force, deformation) can be successfully solved by functionally oriented surface composite materials with thermoelastic martensitic transformations (TMT). The authors proposed the technology of layer-by-layer synthesis of functionally-oriented composite layered materials with TMT in argon environment, implemented on patented equipment in a single technological cycle. This technology determines not only the novelty, but also the economic feasibility of technical solutions. We also suggested step-by-step methods of thermal and thermomechanical treatment of composite layered materials with TMT, which contribute to the structure stabilization while decreasing residual stress. On the basis of complex X-ray diffraction and electron microscopic studies, we determined the structural parameters of High Velocity Oxy-Fuel (HVOF) materials obtained by HVOF with subsequent thermal and thermomechanical treatment and ceramic materials ZrO2-Y2O3-CeO2-Al2O3 stabilized with Al2O3 with subsequent heat treatment. We investigated the microhardness of surface high-entropy and ceramic materials. Tests for "friction-wear" and mechanical high-cycle fatigue of steels with a composite surface laminate showed decrease in the wear rate and increase in the cyclic durability.

Nondestructive Characterization of Nanostructure in Layered Materials Using Synchrotron Radiation

2003 ◽  
Vol 02 (01n02) ◽  
pp. 85-107
Author(s):  
Y. H. Kao ◽  
S. Kim ◽  
Y. L. Soo
Keyword(s):  
Synchrotron Radiation ◽  
Layered Materials ◽  
General Purpose ◽  
X Rays ◽  
Layered Systems ◽  
Practical Applications ◽  
Nondestructive Methods ◽  
Nondestructive Characterization ◽  
Technological Interest

This paper presents a brief review of nondestructive methods useful for the general purpose of characterizing nanostructure in layered materials using x-rays from synchrotron radiation. By way of examples, some practical applications of these methods to the study of layered systems of recent technological interest are demonstrated.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

High Resolution Electron Microscopy of internal interfaces in layered materials

1990 ◽  
Vol 48 (4) ◽  
pp. 320-321
Author(s):  
Yoichi Ishida ◽  
Hideki Ichinose ◽  
Yutaka Takahashi ◽  
Jin-yeh Wang
Keyword(s):  
Grain Boundaries ◽  
Mirror Symmetry ◽  
Functional Materials ◽  
High Resolution Electron Microscopy ◽  
Layered Materials ◽  
Plane Boundary ◽  
Chemical Information ◽  
Layer Plane ◽  
High Tc ◽  
Cubic Metals

Layered materials draw attention in recent years in response to the world-wide drive to discover new functional materials. High-Tc superconducting oxide is one example. Internal interfaces in such layered materials differ significantly from those of cubic metals. They are often parallel to the layer of the neighboring crystals in sintered samples(layer plane boundary), while periodically ordered interfaces with the two neighboring crystals in mirror symmetry to each other are relatively rare. Consequently, the atomistic features of the interface differ significantly from those of cubic metals. In this paper grain boundaries in sintered high-Tc superconducting oxides, joined interfaces between engineering ceramics with metals, and polytype interfaces in vapor-deposited bicrystal are examined to collect atomic information of the interfaces in layered materials. The analysis proved that they are not neccessarily more complicated than that of simple grain boundaries in cubic metals. The interfaces are majorly layer plane type which is parallel to the compound layer. Secondly, chemical information is often available, which helps the interpretation of the interface atomic structure.

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

Compact back-scattered electrons' energy analyzer for standard SEM

1994 ◽  
Vol 52 ◽  
pp. 488-489
Author(s):  
S. Likharev ◽  
A. Kramarenko ◽  
V. Vybornov
Keyword(s):  
Depth Resolution ◽  
High Energy ◽  
Primary Beam ◽  
Layer By Layer ◽  
Energy Analyzer ◽  
High Energy Part ◽  
Small Window ◽  
Energy Part ◽  
Wide Range ◽  
High Voltage Supply

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.

Transmission Electron Microscopy characterization of epitaxial III-V semiconductor thin films grown on Si(100) by ion-assisted deposition

1990 ◽  
Vol 48 (4) ◽  
pp. 686-687
Author(s):  
L. Hultman ◽  
C.-H. Choi ◽  
R. Kaspi ◽  
R. Ai ◽  
S.A. Barnett
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
High Energy ◽  
Nucleation Mechanism ◽  
Layer By Layer ◽  
Extended Defect ◽  
Island Formation ◽  
Si Substrates ◽  
Transmission Electron

III-V semiconductor films nucleate by the Stranski-Krastanov (SK) mechanism on Si substrates. Many of the extended defects present in the films are believed to result from the island formation and coalescence stage of SK growth. We have recently shown that low (-30 eV) energy, high flux (4 ions per deposited atom), Ar ion irradiation during nucleation of III-V semiconductors on Si substrates prolongs the 1ayer-by-layer stage of SK nucleation, leading to a decrease in extended defect densities. Furthermore, the epitaxial temperature was reduced by >100°C due to ion irradiation. The effect of ion bombardment on the nucleation mechanism was explained as being due to ion-induced dissociation of three-dimensional islands and ion-enhanced surface diffusion.For the case of InAs grown at 380°C on Si(100) (11% lattice mismatch), where island formation is expected after ≤ 1 monolayer (ML) during molecular beam epitaxy (MBE), in-situ reflection high-energy electron diffraction (RHEED) showed that 28 eV Ar ion irradiation prolonged the layer-by-layer stage of SK nucleation up to 10 ML. Otherion energies maintained layer-by-layer growth to lesser thicknesses. The ion-induced change in nucleation mechanism resulted in smoother surfaces and improved the crystalline perfection of thicker films as shown by transmission electron microscopy and X-ray rocking curve studies.

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