Microstructure of FCC/BCC Metal Multilayers

1989 ◽  
Vol 160 ◽  
Author(s):  
Nigel M. Jennett ◽  
D.J. Dingley ◽  
Y. Ando
Keyword(s):  
Substrate Temperature ◽  
Magnetic Moment ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Bcc Lattice ◽  
A Value ◽  
Fcc Lattice ◽  
Temperature Window ◽  
Backing Layer

AbstractBilayers of Cu/Fe and Cu/V and multilayers of Ni/Fe have been grown under high vacuum and ultra high vacuum conditions respectively with [111] epitaxy. Multilayer layer thicknesses ranged from 3 monolayers to 15 monolayers per layer. Improved epitaxy of the UHV growth was, we believe, due to the better vacuum although perfect material could only be obtained for growth within a narrow and shifting substrate temperature ‘window’. Possible shortfall in the quality of the Cu backing layer epitaxy was averted by a 2hr anneal at 425°C.In the Fe/Ni multilayers the Fe was observed to adopt the FCC lattice rather than the equilibrium BCC lattice for layer thicknesses less than 10 monolayers. This change of structure coincided with a reduction in sample magnetic moment per volume attributed to a collapse of the Fe moment to a value 7 times less than bulk.

Effects of Substrate Temperature and Atomic Hydrogen Flow on the Mircocrystallinity of Evaporated Hydrogenated silicon Films

2002 ◽  
Vol 715 ◽  
Author(s):  
A.J. Stoltz ◽  
Whitney Mason ◽  
J.D. Benson ◽  
J.H. Dinan ◽  
K. McCormack ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Atomic Hydrogen ◽  
High Vacuum ◽  
Electron Beam Evaporation ◽  
Ultra High Vacuum ◽  
Hydrogenated Silicon ◽  
Hydrogen Flow ◽  
A Value ◽  
Hydrogenated Amorphous

AbstractAs a first step toward an understanding of the chemical and structural role of hydrogen in hydrogenated amorphous silicon, we utilized electron beam evaporation in an ultra high vacuum environment to deposit films of amorphous silicon and systematically dosed these films with atomic hydrogen during deposition. Secondary Ion Mass Spectroscopy (SIMS) data indicated that hydrogen concentration can be varied from the detection limit of SIMS to a value in excess of 1021 atoms cm-3. The intentional addition of hydrogen caused the concentration to fall from in an excess of 1021 atoms*cm-3 to below 1018 atoms*cm-3.

Untersuchungen zur Epitaxie dünner Goldaufdampfschichten auf Alkalihalogeniden im Ultrahochvakuum

1968 ◽  
Vol 23 (10) ◽  
pp. 1526-1536 ◽  
Author(s):  
R. W. Adam
Keyword(s):  
Substrate Temperature ◽  
Crystal Orientation ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Gold Films ◽  
Oriented Growth ◽  
Deposition Rates ◽  
Deposition Parameters ◽  
Temperature Deposition ◽  
Substrate Temperatures

In the present paper the oriented growth of gold on alkalihalides, cleaved in ultra high vacuum has been investigated. The dependence of the crystal orientation on the deposition parameters substrate temperature, deposition rate, and the physical properties of the substrate were studied systematically. At suitable substrate temperatures and deposition rates it was possible to obtain epitaxial gold films on KCl, KBr and KJ.

Are major instrumental developments in TEM still to be Expected?

1988 ◽  
Vol 46 ◽  
pp. 646-647
Author(s):  
K.D. van der Mast ◽  
A.J. Koster
Keyword(s):  
Surface Science ◽  
New Technologies ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Analytical Instrument ◽  
Electron Efficiency ◽  
In Situ Experiments ◽  
New Ideas

In general instrumental developments are caused either by new application demands or by the availability of new technologies. If we investigate the trends in application demands, some predictions can be made safely: More and more the TEM will be used as an analytical instrument. The number of desired signals (detectors) will increase and the quality of the signals must be improved in terms of noise and electron efficiency. Examples are parallel collection EELS and Auger detectors (Kruit and Venables, 1988).The first experiments on coincidence techniques are also promising (Kruit et al, 1984) and exciting new ideas are investigated today. Besides this, another area of applications will probably become more important: surface science in situ experiments. Especially for this type of experiments it is difficult to transfer the specimen to another system without spoiling the experiment. So these applications will lead to an ultra high vacuum specimen environment - constructed in a way that many accessories necessary for surface experiments can be added: Ion guns, preparation chamber, knudsen cells etc.

In-Situ Caiciss Study Of Dynamic Process Of Oxygen Desorption On TiO2-Terminated SrTiO3(001) Surface

1997 ◽  
Vol 474 ◽  
Author(s):  
T. Nishihara ◽  
O. Ishiyama ◽  
S. Hayashi ◽  
M. Shinohara ◽  
M. Yoshimoto ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Room Temperature ◽  
Incident Angle ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ion Scattering ◽  
Peak Intensity ◽  
Ion Scattering Spectroscopy ◽  
Topmost Layer

ABSTRACTThe topmost atoms of TiO2 - terminated SrTiO3(001) annealed at temperatures between room temperature and 800°C in ultra high vacuum (UHV), have been studied by means of in-situ coaxial impact collision ion scattering spectroscopy (CAICISS). Both time-of-flight spectra at the incident angle of 45.0°C along [ 100] azimuth and of 35.3°C along [110] azimuth revealed Ti and weak O peaks and no Sr peak at 150°C, which means that the topmost layer at 150°C is terminated by TiCh-plane, completely. On the other hand, as increasing the substrate temperature, Sr peak began to appear above 400°C. This Sr peak intensity from both directions was drastically increased with elevating the substrate temperature. This indicates that the topmost O and Ti atoms desorb from the surface at the higher substrate temperature. The ratio Sr/Ti corresponds to the amount of the topmost oxygen or titanium vacancies due to the desorption. It was found that 40 % of the topmost oxygen atoms and 32% of the topmost titanium atoms desorb from TiO2-terminated SrTiO3(001) surface at 800°C. The activation energies for oxygen and titanium desorption were 0.28eV and 0.40eV, respectively.

The growth of gallium arsenide on Si(100) by molecular-beam epitaxy

1987 ◽  
Vol 65 (8) ◽  
pp. 904-908 ◽  
Author(s):  
W. T. Moore ◽  
R. L. S. Devine ◽  
P. Maigné ◽  
D. C. Houghton ◽  
J.-M. Baribeau ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Vacuum ◽  
Group Iv ◽  
Ultra High Vacuum ◽  
Buffer Layers ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
X Ray

The growth of GaAs on Si(100) directly and with Ge buffer layers has been carried out sequentially under ultra high vacuum conditions in a double-ended III–V and group IV molecular beam epitaxy system. These heterostructures were examined by cross-section transverse emission microscopy, Rutherford backscattering, X-ray diffraction, and photoluminescence spectroscopy.Dislocation densities were observed to be high [Formula: see text] near both the GaAs–Si and the Ge–Si interfaces and to decrease to ~5 × 108 cm−2 a few micrometres from these interfaces. No dislocations were observed to originate at the GaAs–Ge interface, but the threading dislocations existing in the Ge buffer layer were found to propagate across this interface without significant deviation. The crystalline quality of the GaAs grown on Ge buffer layers was comparable with that grown on Si directly. However, GaAs has not yet been grown on the highest quality Ge buffer layers obtainable.

CRYSTALLINE AgInSe2 FILMS ON GLASS BY LASER ABLATION

2010 ◽  
Vol 24 (27) ◽  
pp. 5379-5385 ◽  
Author(s):  
DINESH PATHAK ◽  
R. K. BEDI ◽  
AJAY KAUSHAL ◽  
DAVINDER KAUR
Keyword(s):  
Laser Ablation ◽  
Substrate Temperature ◽  
High Vacuum ◽  
Compositional Analysis ◽  
Ultra High Vacuum ◽  
X Ray Diffraction ◽  
High Quality ◽  
Glass Substrates ◽  
Complex Element ◽  
Formation Technique

Laser ablation has attracted special interest for the formation of thin films compared with other formation technique. A distinctive feature of laser ablation is that it allows high quality and stoichiometry of films of even very complex element material. In this presentation, laser ablation of AgInSe 2 chalcopyrite semiconductor will be discussed in which it is difficult to maintain stoichiometry by conventional method. High Quality AgInSe 2 (AIS) films were grown on Glass substrates by the ultra-high-vacuum pulsed laser deposition technique from the AIS target synthesized from high-purity materials. The X-ray diffraction studies of the films show that films are textured in (112) direction. The substrate temperature appears to influence the properties of films. Increase in substrate temperature results in a more ordered structure. Compositional analysis has been carried out by EDAX. It is observed that compositional stoichiometry is maintained to a greater extent by PLD technique than other traditional methods like thermal evaporation. The optical studies of the films show that the optical band gap is about 1.20 eV.

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