On the Coercivity of Granular Fe-SiO2 Films

1988 ◽  
Vol 132 ◽  
Author(s):  
S. H. Liou ◽  
C. H. Chen ◽  
H. S. Chen ◽  
A. R. Kortan ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Substrate Temperature ◽  
High Substrate Temperature ◽  
Linear Temperature ◽  
Sio2 Films ◽  
High Substrate ◽  
Transmission Electron ◽  
Substrate Temperatures

ABSTRACTThe coercivity of granular Fe embedded inside an SiO2 matrix was as high as 3 kOe at 6K, and 1.1 kOe at 300K. In this study, we observed a linear temperature (T) dependence of the coercivity for the samples prepared at a high substrate temperature (773K), and a T1/2 dependence of the coercivity for the sample prepared at a low substrate temperature (473K). This indicates that the microstructures of films prepared at different substrate temperatures are not the same. This phenomenon can be explained if we assume that there are interconnections between particles for the sample prepared at a high substrate temperature. We looked for evidence of interconnections between particles with transmission electron microscopy (TEM).

Microstructures of YBCO Thin Films Prepared by Pulsed Organometallic Beam Epitaxy

1992 ◽  
Vol 275 ◽  
Author(s):  
J. G. Hu ◽  
D. J. Miller ◽  
D. B. Buchholz ◽  
S. J. Duray ◽  
D. Schulz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Substrate Temperature ◽  
Low Temperatures ◽  
Controlled Growth ◽  
High Substrate ◽  
Ybco Thin Films ◽  
Transmission Electron ◽  
Substrate Temperatures

ABSTRACTThe microstructure of Y1Ba2Cu3Oy films and Y1Ba2Cu3Oy / Pr1Ba2Cu3Oy multilayers prepared by a pulsed organometallic beam epitaxy (POMBE) technique have been characterized by transmission electron microscopy (TEM). The microstructure of the films is observed to vary as a function of substrate temperature. At low temperatures, films are polycrystalline and exhibit some impurity phases. At higher substrate temperatures, films grow epitaxially with smooth surfaces and few impurities. Controlled growth at sufficiently high substrate temperatures allows uniform growth of alternating Y1Ba2Cu3Oy and Pr1Ba2Cu3Oy layers.

Photo Modified Growth of GaAs by Chemical Beam Epitaxy

1998 ◽  
Vol 510 ◽  
Author(s):  
R. Jothilingam ◽  
T. Farrell ◽  
T.B. Joyce ◽  
P.J. Goodhew
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Rate ◽  
Electrical Power ◽  
Xenon Lamp ◽  
Chemical Beam Epitaxy ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Laser Reflectometry

AbstractWe report the photo modified growth of GaAs by chemical beam epitaxy at substrate temperatures in the range 335 to 670°C using triethygallium (TEG) and arsine. A mercury-xenon lamp (electrical power 200 W) provided the irradiation for the photoassisted growth. The growth was monitored in real time by laser reflectometry (LR) using a 670 nm semiconductor laser, and the optically determined growth rate agreed with that obtained from the layer thickness measured by cross sectional transmission electron microscopy. The observed photo-enhancement of the growth rate at low substrate temperatures and inhibition at high substrate temperatures is thermal in origin, consistent with raising the substrate temperature by 10±3°C. Cross sectional transmission electron microscopy showed that the photoassisted layers are essentially free from dislocations

Structure of vacuum-deposited Zn3P2 films

1986 ◽  
Vol 64 (10) ◽  
pp. 1369-1373 ◽  
Author(s):  
U. von Sacken ◽  
D. E. Brodie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Substrate Temperature ◽  
Columnar Structure ◽  
Major Effect ◽  
Film Structure ◽  
Electron Bombardment ◽  
Initial Growth ◽  
Transmission Electron

The structure of polycrystalline Zn3P2 films has been studied for 1- to 2-μm-thick vacuum-deposited films on glass substrates. Transmission electron microscopy and X-ray diffraction techniques have been used to obtain a detailed, quantitative analysis of the film structure. The initial growth consists of small (≤ 10 nm), randomly oriented grains. As the film thickness increases, the growth of crystallites with the {220} planes oriented approximately parallel to the substrate is favoured, and a columnar structure develops along with a highly preferred orientation. This structure has been observed directly by transmission electron microscopy of thin cross sections of the films. The size of the grains at the free surface increases with the film thickness, reaching approximately 200–300 nm when the film is 1 μm thick. The effects of substrate temperature and low-energy (0.5–2 keV) electron bombardment of the film during growth have also been studied. Neither substrate temperature nor electron bombardment appear to have a major effect on the film structure. The primary effect of electron bombardment appears to be the creation of preferred nucleation sites on the substrate.

Formation of Microcrystalline Silicon film by RMS Process

1989 ◽  
Vol 164 ◽  
Author(s):  
Cheng Wang ◽  
G.N. Parsons ◽  
E.C. Buehler ◽  
R.J. Nemanich ◽  
G. Lucovsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Film ◽  
Reactive Magnetron ◽  
Growth Mechanisms ◽  
Microcrystalline Silicon ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Microcrystalline Silicon Film ◽  
Deposition Conditions

AbstractWe have deposited microcrystalline, gc-Si, silicon films by using RF reactive magnetron sputtering (RMS) at high substrate temperatures, Ts > 500°C, and at a relatively low partial pressure of hydrogen, PH = 0.40 mTorr, and at low Ts ∼200- 300°C, but with a higher PH > 2 mTorr. We have detected μc-crystallinity by Raman scattering and transmission electron microscopy. We discuss differences in the growth mechanisms for formation of μc-Si under these two deposition conditions.

Mg–Ti–spinel formation by interfacial solid-state reaction at the TiN/MgO interface

1989 ◽  
Vol 4 (5) ◽  
pp. 1266-1271 ◽  
Author(s):  
L. Hultman ◽  
J-E. Sundgren ◽  
D. Hesse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Reactive Magnetron ◽  
Cross Sectional ◽  
Tin Films ◽  
Spinel Formation ◽  
Transmission Electron ◽  
Spinel Composition ◽  
Substrate Temperatures

Mg–Ti–spinel formation has been observed by cross-sectional transmission electron microscopy at the interface of TiN(100) films and MgO(100) substrates for films grown at substrate temperatures higher than 800 °C and for samples post-annealed at 850 °C. The TiN films were deposited by reactive magnetron sputtering onto cleaved (100)-oriented MgO substrates. The spinel formed 5 nm epitaxial layers along the interface with occasional (111) wedges growing into the MgO. The orientational relationships were found to be TiN(100)|spinel(100)|MgO(100) and TiN[001]|spinel[001]|MgO[001]. The spinel composition is suggested to be Mg2TiO4.

Pyrolytic and Laser Photolytic Growth of Crystalline and Amorphous Germanium Films from Digermane (Ge2H6)

1988 ◽  
Vol 131 ◽  
Author(s):  
Djula Eres ◽  
D. H. Lowndes ◽  
J. Z. Tischler ◽  
J. W. Sharp ◽  
D. B. Geohegan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Purity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Partial Pressures ◽  
193 Nm ◽  
Substrate Temperatures ◽  
Deposition Conditions

ABSTRACTHigh-purity digermane (Ge2H6, 5% in He) has been used to grow epitaxially oriented crystalline Ge films by pyrolysis. Amorphous Ge:H films also have been deposited by pyrolysis and ArF (193 nm) laser-induced photolysis. The amorphous-to-crystalline transition and the film's morphology was studied as a function of deposition conditions. The film's microstructure, strain and epitaxial quality were assessed using x-ray diffraction curves and scanning and transmission electron microscopy. It was found that commensurate, coherently strained epitaxial Ge films could be grown pyrolytically on (100) GaAs at low (0.05–40 m Torr) Ge2H6 partial pressures, for substrate temperatures above 380°C.

Transmission Electron Microscopy and X-Ray Diffraction Studies of a,b-Axis Oriented YBa2Cu3O7-δ Films

1992 ◽  
Vol 275 ◽  
Author(s):  
S. K. Streiffer ◽  
B. M. Lairson ◽  
E. M. Zielinski ◽  
J. C. Bravman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Microscopy Data ◽  
Film Substrate ◽  
Substrate Temperatures ◽  
High Resolution Microscopy

ABSTRACTQuantitative high resolution transmission electron microscopy and x-ray diffraction have been used to study films of YBa2Cu3O7-δ grown on LaAlO3 substrates at low substrate temperatures. Based on analysis of high-resolution micrographs, it is asserted that the films are b-axis oriented near the film-substrate interface, and switch to a-axis oriented at some distance away from the interface, in a manner which varies from sample to sample. Thus, the films undergo a change in orientation as a function of distance from the substrate. X-ray diffraction confirms that these films contain both a-axis oriented and b-axis oriented components normal to the plane of the substrate, consistent with the high-resolution microscopy data.

Growth of Metamorphic InGaP for Wide-Bandgap Photovoltaic Junction by MBE

2010 ◽  
Vol 1268 ◽  
Author(s):  
John Simon ◽  
Stephanie Tomasulo ◽  
Paul Simmonds ◽  
Manuel J Romero ◽  
Minjoo Larry Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Wide Bandgap ◽  
Threading Dislocation ◽  
Step Size ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Substrate Temperatures

AbstractMetamorphic triple-junction solar cells can currently attain efficiencies as high as 41.1%. Using additional junctions could lead to efficiencies above 50%, but require the development of a wide bandgap (2.0-2.2eV) material to act as the top layer. In this work we demonstrate wide bandgap InyGa1-yP grown on GaAsxP1-x via solid source molecular beam epitaxy. Unoptimized tensile GaAsxP1-x buffers grown on GaAs exhibit asymmetric strain relaxation, along with formation of faceted trenches 100-300 nm deep in the [01-1] direction. Smaller grading step size and higher substrate temperatures minimizes the facet trench density and results in symmetric strain relaxation. In comparison, compressively-strained graded GaAsxP1-x buffers on GaP show nearly-complete strain relaxation of the top layers and no evidence of trenches. We subsequently grew InyGa1-yP layers on the GaAsxP1-x buffers. Photoluminescence and transmission electron microscopy measurements show no indication of phase separation or CuPt ordering. Taken in combination with the low threading dislocation densities obtained, MBE-grown InyGa1-yP layers are promising candidates for future use as the top junction of a multi-junction solar cell.

Free-standing SiO2 films containing Si nanocrystals directly suitable for transmission electron microscopy

2008 ◽  
Vol 39 (3-4) ◽  
pp. 518-522 ◽  
Author(s):  
S. Novikov ◽  
J. Sinkkonen ◽  
T. Nikitin ◽  
L. Khriachtchev ◽  
M. Räsänen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Free Standing ◽  
Sio2 Films ◽  
Transmission Electron ◽  
Si Nanocrystals
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