Site exchange in ultrathin layers of Ni on Cu(100) studied with element-specific layer-by-layer resolution

2003 ◽  
Vol 67 (15) ◽  
Author(s):  
T. C. Q. Noakes ◽  
P. Bailey ◽  
G. van der Laan
Keyword(s):  
Layer By Layer ◽  
Ultrathin Layers ◽  
Site Exchange

Characterization of carbon dioxide separation membrane with polycation nano-layers

2013 ◽  
Vol 1492 ◽  
pp. 137-142
Author(s):  
Tatsuya Funaoka ◽  
Yusuke Daiko ◽  
Atsushi Mineshige ◽  
Tetsuo Yazawa
Keyword(s):  
Carbon Dioxide ◽  
Silica Film ◽  
Ideal Gas ◽  
Layer By Layer ◽  
Carbon Dioxide Absorption ◽  
Carbon Dioxide Separation ◽  
Separation Membrane ◽  
Ultrathin Layers ◽  
Assembly Technique ◽  
Unmodified Silica

ABSTRACTUltrathin layers of positively charged poly(diallyl dimethylammonium) choloride (PDDA) and negatively charged poly(sodium 4-styrenesulfonate) (PSS) were deposited on SiO2/ polyethylene glycol hybrid membranes via layer-by-layer assembly technique, and carbon dioxide absorption/separation properties were investigated. Quartz crystal microbalance (QCM) measurements revealed that both PDDA and PSS nanocoatings have a good affinity for CO2 absorption. PDDA-deposited film shows about two times higher CO2 ideal gas selectivity compared with unmodified silica film.

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.

Role of Oxygen Adatoms in Homoepitaxial Growth of Cu(001)

1998 ◽  
Vol 528 ◽  
Author(s):  
Masanori Yata ◽  
Herve Rouch ◽  
Keikichi Nakamura
Keyword(s):  
Exchange Rate ◽  
Transition Temperature ◽  
Barrier Height ◽  
Deposition Rate ◽  
Layer By Layer ◽  
Step Flow ◽  
Homoepitaxial Growth ◽  
Arrhenius Relation ◽  
Site Exchange

AbstractO atoms segregate to the surface during Cu homoepitaxial growth on Cu(001)-(2√2×√2)-O to retain the (2√2×√2) surface. The presence of an O adlayer on the Cu surface raises the barrier height for the surface diffusion of the Cu adatom and increases the transition temperature of the growth mode from step flow to layer by layer. The growth proceeds by site exchange between Cu adatoms and O atoms. The site-exchange rate competes with the Cu deposition rate. There exists a critical Cu deposition rate above which the O atoms can not exchange the sites with Cu adatoms. The critical Cu deposition rate obeys an Arrhenius relation and the active energy for the site-exchange is estimated at 0.66 eV.

Superconducting Multilayer Structures Grown by All-Mbe

1992 ◽  
Vol 275 ◽  
Author(s):  
I. Bozovic ◽  
J. N. Eckstein ◽  
M. E. Klausmeier-Brown ◽  
G. F. Virshup ◽  
K. S. Rails
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Atomic Layer ◽  
Multilayer Structures ◽  
Layer By Layer ◽  
Ultrathin Layers ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Sharp Interfaces

ABSTRACTThin films of various Bi-Sr-Ca-Cu-O (2201, 2212,…, 2–2–11–12) compounds have been synthesized using atomic-layer-by-layer molecular beam epitaxy (ALL-MBE). Single-crystal films with excellent transport properties, smooth surfaces and atomically sharp interfaces in multilayer structures have been obtained. That made it possible to deposit virtually perfect ultrathin layers and superlattices, and fabricate hysteretic Josephson junctions from SIS multilayers.

Growth, Structure and Characterization of Electrodeposited Co/Cu Ultrathin Films and Multilayers

1996 ◽  
Vol 451 ◽  
Author(s):  
Y. Jyoko ◽  
S. Kashiwabara ◽  
Y. Hayashi
Keyword(s):  
Multilayered Structure ◽  
Layer Growth ◽  
Layer By Layer ◽  
Potential Control ◽  
Spacer Layer Thickness ◽  
Ultrathin Layers ◽  
Spacer Layer ◽  
Reflection Electron Microscopy ◽  
Slight Amount

ABSTRACTPreparation of giant magnctorcsistancc Co/Cu multilayers by electrodeposition has been discussed on the basis of a nucleation- growth mechanism and experimental observations. Reflection electron microscopy (REM- RHEED) studies of clectrodcpositcd Co, Cu/Pt(111) ultrathin layers and bilayers have revealed a simultaneous multinuclcar multilayer growth (pseudo layer- by- layer growth). REM- RHEED observations have also suggested the formation of an additional (2×2) superstructure on an epitaxially grown Cu/Co/Pt(111) bilayer surface. “Giant” magnctorcsistancc and oscillatory antifcrramagnetic intcrlaycr coupling have been observed in a (111) textured Co/Cu multilayered nanostructurc, prepared by electrodeposition under potential control in the presence of a very slight amount of CrO3. Such a multilayered structure containing a nominal nonmagnetic Cu spacer layer thickness of 3.2 nm exhibits a large saturation magnctorcsistancc of more than 18% at room temperature.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document