Microstructural characterization of thick YBa2Cu3O7−δ films on improved rolling-assisted biaxially textured substrates

2003 ◽  
Vol 18 (7) ◽  
pp. 1723-1732 ◽  
Author(s):  
K. J. Leonard ◽  
S. Kang ◽  
A. Goyal ◽  
K. A. Yarborough ◽  
D. M. Kroeger
Keyword(s):  
Seed Layer ◽  
Pulsed Laser ◽  
Microstructural Characterization ◽  
Stabilized Zirconia ◽  
Cross Sectional ◽  
Ybco Films ◽  
Transmission Electron ◽  
Critical Current Density Jc

The microstructural changes associated with the reduced dependence of critical current density (Jc) versus thickness of thick, epitaxial YBa2Cu3O7–δ (YBCO) films on rolling-assisted biaxially textured substrates (RABiTS) were investigated. Pulsed laser deposited YBCO films varying in thickness from 1.0 to 6.4 ?m on RABiTS with an architecture of Ni–3 at.% W/Y2O3/yttrium-stabilized-zirconia/CeO2/YBCO were prepared for cross-sectional transmission electron microscopy studies. Dramatic improvements in physical properties and microstructural quality were observed resulting from the use of Ni–3 at.% W substrates, which provided a sharper texture over earlier Ni substrates, and replacement of CeO2 with Y2O3 as the seed layer within the buffers. The YBCO films showed exceptional orientation up to 6.4 μm thickness, with no misoriented grains or dead layers observed and only limited reaction between the YBCO and CeO2 cap layer. The high quality of the films was also attributed in part to the formation of a tungsten oxide layer forming at the top of the Ni–3% W substrate, limiting the growth of deleterious NiO into the conductor.

Microstructural Characterization of Ni-Al Alloyed Layer under Laser Rapid Solidification Condition

2011 ◽  
Vol 328-330 ◽  
pp. 565-568
Author(s):  
Yue Yang ◽  
Hua Wu
Keyword(s):  
Cross Section ◽  
Pulsed Laser ◽  
Microstructural Characterization ◽  
Eutectic Growth ◽  
Nickel Layer ◽  
Solidification Condition ◽  
Melted Zone ◽  
Transmission Electron ◽  
Pulsed Laser Irradiation

Nickel layer electroless deposited on aluminum substrate was alloyed by Nd-YAG pulsed laser irradiation. Solidification microstructure was characterized through cross section, showing typical microstructure that were located in upper and middle melted zone and interface of melted pool and substrate, respectively. The microstructure was analyzed by transmission electron microscopy (TEM). Followed by the observations, the eutectic growth process was analyzed.

MBE Growth and Optical Characterization of InGaN/AlGaN Multiquantum Wells

1996 ◽  
Vol 449 ◽  
Author(s):  
R. Singh ◽  
W.D. Herzog ◽  
D. Doppalapudi ◽  
M.S. ÜnlÜ ◽  
B.B. Goldberg ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Electron Cyclotron Resonance ◽  
Temperature Cycling ◽  
Cross Sectional ◽  
Luminescence Microscopy ◽  
Mbe Growth ◽  
Transmission Electron ◽  
Ingan Quantum Wells

ABSTRACTWe report the growth of InGaN/AIGaN MQWs on c-plane sapphire by electron cyclotron resonance assisted molecular beam epitaxy (ECR-MBE). Two types of structures were investigated; one employing a GaN and the other a A1GaN barrier layer. The first structure consists of five periods of 80 Å thick In0.09Ga0.91N wells separated by 90 Å thick GaN barriers. The second structure consists of|seven periods of 120 Å thick In0.35Ga0.65N wells and Al0.1Ga0.9N barriers. The substrate temperature was kept constant during the growth of both the wells and the barriers, thus avoiding the need for any temperature cycling during the growth, which may lead to interfacial contamination. The films were characterized by cross sectional transmission electron microscopy (TEM), room temperature photoluminescence (PL) and sub-micron resolution luminescence microscopy. TEM images show sharp and abrupt interfaces, thus confirming the high interfacial quality of the MQW structures. Both structures exhibit strong RT luminescence emission peaking at 387 nm (FWHM = 16nm) for the In0.09Ga0.91N/GaN structure and at 463 nm (FWHM = 28nm) for the In0.35Ga0.65N/A10.1Ga0 9N structure. The high resolution luminescence microscopy studies reveal that the radiative recombination for the InGaN quantum wells is 60–70 times more efficient than for the underlying GaN film.

Microstructural Characterization of 3C-SiC Thin Films Grown by Flash Lamp Induced Liquid Phase Epitaxy

2005 ◽  
Vol 483-485 ◽  
pp. 295-298 ◽  
Author(s):  
Gabriel Ferro ◽  
D. Panknin ◽  
Efstathios K. Polychroniadis ◽  
Yves Monteil ◽  
Wolfgang Skorupa ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
Structural Characteristics ◽  
Microstructural Characterization ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Thin 3C-SiC films epitaxially grown on Si-substrate are substantially improved by the FLASIC process, which involves irradiation with flash lamps with pulse duration of 20ms. The disadvantages of the standard FLASIC process are the undulations introduced in the SiC film due to melting of the Si-substrate and the Si mass transport near the SiC/Si interface during the flash. An improved structure was realised in order to minimize the undulations of the SiC, improving also the quality of the film. This structure involves the deposition of a silicon overlayer (SOL) on the initial SiC layer, followed by an additional SiC capping layer acting as a source for SiC transfer by liquid phase epitaxy to the lower SiC layer. Significant mass SiC transport from the upper to the lower SiC layer through the SOL occurs during the flash. The new structure is characterized as inverse - FLASiC. The structural characteristics of the new structure were studied by transmission electron microscopy and atomic force microscopy.

Nucleation and Growth of {113} Defects and {111} Dislocation Loops Insilicon-Implanted Selicon

1997 ◽  
Vol 469 ◽  
Author(s):  
G. Z. Pan ◽  
K. N. Tu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microstructural Characterization ◽  
Nucleation And Growth ◽  
Growth Behavior ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

ABSTRACTPlan-view and cross-sectional transmission electron microscopy have been used to study the microstructural characterization of the nucleation and growth behavior of {113} rodlike defects, as well as their correlation with {111} dislocation loops in silicon amorphized with 50 keV, 36×1014 Si/cm2, 8.0 mAand annealed by rapid thermal anneals at temperatures from 500 °C to 1100 °C for various times. We found that the nucleations of the {113} rodlike defects and {111} dislocation loops are two separate processes. At the beginning of anneals, excess interstitials accumulate and form circular interstitial clusters at the preamorphous/crystalline interface at as low as 600 °C for 1 s. Then these interstitial clusters grow along the <110> direction to form {113} rodlike defects. Later, while the {113} defects have begun to grow and/or dissolve into matrix, the {111} faulted Frank dislocation loops start to form. We also found that the initial interstitial clusters prefer to grow along the <110>directions inclined to the implantation surface.

Characterization of Thermoelectric Ca3Co4O9 Microstructure Using Transmission Electron Microscopy

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
T Paulauskas ◽  
R.F. Klie
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stacking Faults ◽  
Pulsed Laser ◽  
Crystal Defects ◽  
Laser Deposition ◽  
Transmission Electron

Ca3Co4O9 (CCO), a misfit layered structure exhibiting large Seebeck coefficient at temperatures up to 1000 K has attracted increasing attention as a novel high-temperature thermoelectric material. In this work, we investigate bulk CCO as well as thin CCO films grown on SrTiO3 (001) and Al2O3 (0001) using pulsed laser deposition. Resulting crystal structure and quality of the samples is examined using high-resolution transmission electron microscopy in order to correlate with thermoelectric properties. HRTEM images show incommensurate stacks of CdI2-type CoO2 layers alternating with rock-salt-type Ca2CoO3 layers along the c-axis. A natural buffer layer about 10 nm thick was found present between CCO and SrTi3 substrate accompanied by higher density of stacking faults. The CCO grown on Al2O3 exhibited numerous misoriented grains, crystal defects and presence of CaxCoO2 phase.

Microstructural Characterization of Low Temperature GaAs(111)B MBE Growth by AFM and Tem

1992 ◽  
Vol 280 ◽  
Author(s):  
M. P. de Boer ◽  
J. E. Angelo ◽  
A. M. Dabiran ◽  
P. I. Cohen ◽  
W. W. Gerberich
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Cross Sectional ◽  
Plan View ◽  
Mbe Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTAtomic Force Microscopy (AFM) images are correlated with Transmission Electron Microscopy (TEM) plan-view images in a structure consisting of <111> oriented GaAs layers grown by molecular beam epitaxy (MBE) at 500°C. We present results on the applicability of AFM, which requires short sample preparation and imaging time relative to TEM, in obtaining information on twin density and growth pits of these low temperature samples. Also, we discuss the behavior of twin boundaries by comparing plan-views and cross sectional TEM images.

Microstructural characterization of reactions in Al–Zr thin film couples

1993 ◽  
Vol 8 (2) ◽  
pp. 274-285 ◽  
Author(s):  
K.P. Mingard ◽  
B. Cantor
Keyword(s):  
Thin Film ◽  
Reaction Layer ◽  
Microstructural Characterization ◽  
Amorphous Layer ◽  
The Novel ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Two Stages

The mechanisms of reaction in sputter-deposited Al–Zr thin film couples have been investigated using extensive transmission electron microscopy (TEM) observations of cross-sectional specimens prepared by the novel use of an ultramicrotome. The TEM observations greatly facilitated understanding of composition-depth profiles obtained by Rutherford backscattering spectroscopy (RBS). The reaction between Al and Zr in thin films, and the influence of Cu on this reaction, was shown by the TEM to be much more complex than previously reported in studies that largely used RBS. Reaction of Al and Zr in sputter-deposited films occurs in two stages. Initially reaction occurs by growth of an amorphous layer at the Zr interface and is promoted by intermixing of Al and Zr during deposition. Growth of an amorphous layer in an Al-transition metal thin film couple has not been reported previously. Subsequently, the amorphous layer is consumed by growth of microcrystalline Al3Zr from the Zr/reaction layer interface. The transition from growth of amorphous to microcrystalline Al3Zr results in thickening of the reaction layer with an overall growth rate exponent of 1/3. The Al3Zr grows with the metastable L12 cubic structure, except in the presence of Cu, when it grows with the tetragonal DO23 structure. The fine initial Al and Zr grain sizes limit the influence of Cu on the morphology of the reaction; in all cases, a continuous and uniform reaction layer thickness is observed by TEM.

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.

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

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