Room-temperature epitaxy of Cu on Si(111) using partially ionized beam deposition

1990 ◽  
Vol 5 (5) ◽  
pp. 989-997 ◽  
Author(s):  
P. Bai ◽  
G-R. Yang ◽  
L. You ◽  
T-M. Lu ◽  
D.B. Knorr
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Intermediate Phase ◽  
X Ray Diffraction ◽  
Lattice Matching ◽  
Partially Ionized ◽  
Simple Picture ◽  
Matching Concept ◽  
Beam Deposition

The epitaxial growth of Cu on Si(111) substrate at room temperature was achieved using the Partially Ionized Beam (PIB) deposition technique in a conventional (10−4 Pa) vacuum without prior in situ cleaning of the substrate or post-annealing of the film. The beam contained ≍2% of Cu self-ions, and a bias of 0 to 4.2 kV was applied to the substrate during deposition. X-ray diffraction studies showed the existence of a twin structure in the epitaxial Cu layer deposited at 1 kV. A mechanism of epitaxial growth of Cu(111) on Si(111) substrate via an η″—Cu3Si intermediate phase is proposed. Based on the crystal structure of η″—Cu3Si, it is demonstrated that the geometrical lattice matching concept provides a simple picture of lattice continuity at the interface in this epitaxial system.

scholarly journals Synthesis and Characterization of 12CaO·7Al2O3 Slags: The Effects of Impurities and Atmospheres on the Phase Relations

2020 ◽  
Vol 51 (6) ◽  
pp. 2689-2710
Author(s):  
Fabian Imanasa Azof ◽  
Kai Tang ◽  
Jinglin You ◽  
Jafar Safarian
Keyword(s):  
Room Temperature ◽  
Intermediate Phase ◽  
Atmospheric Conditions ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
Electron Probe Micro Analyzer ◽  
Low Concentrations ◽  
A Minor

AbstractSynthesis of crystalline slags of 12CaO·7Al2O3 phase from the corresponding melt compositions in different atmospheric conditions and different purities is investigated. Observations using a thermogravimetry coupled with differential thermal analysis showed that the dehydration of a zeolitic 12CaO·7Al2O3 phase occur at 770 °C to 1390 °C before it congruently melts at 1450 °C. The X-ray diffraction pattern of the slag showed that a single 12CaO·7Al2O3 phase is produced from a mixture, which has small SiO2 impurity with a 49:51 mass ratio of CaO to Al2O3. A scanning electron microscope and electron probe micro-analyzer showed that a minor Ca-Al-Si-O-containing phase is in equilibrium with a grain-less 12CaO·7Al2O3 phase. Moreover, 12CaO·7Al2O3 is unstable at room temperature when the high-purity molten slag is solidified under oxidizing conditions contained in an alumina crucible. On the other hand, a high-temperature in-situ Raman spectroscopy of a slag that was made of a higher purity CaO-Al2O3 mixture showed that 5CaO·3Al2O3 phase is an unstable/intermediate phase in the the CaO-Al2O3 system, which is decomposed to 12CaO·7Al2O3 above 1100 °C upon heating in oxidizing conditions. It was found that 5CaO·3Al2O3 is present at room temperature when the 12CaO·7Al2O3 dissociates to a mixture of 5CaO·3Al2O3, 3CaO·Al2O3, and CaO·Al2O3 phases during the cooling of the slag at 1180 °C ± 20 °C in reducing atmosphere. It is proposed that low concentrations of Si stabilize 12CaO·7Al2O3 (mayenite), in which Si is a solid solution in its lattice, which is named Si-mayenite. Regarding the calculated CaO-Al2O3-SiO2 diagram in this study, this phase may contain a maximum of 4.7 wt pct SiO2, which depends on the total SiO2 in the system and the Ca/Al ratio.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

In Situ Synchrotron X-Ray Diffraction Study of a Deformed Cu-Fe-P Alloy during Heating

2016 ◽  
Vol 850 ◽  
pp. 191-196 ◽  
Author(s):  
Wei Wang ◽  
Cun Lei Zou ◽  
Ren Geng Li ◽  
Wen Wen ◽  
Hui Jun Kang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lattice Distortion ◽  
Copper Matrix ◽  
Heating Process ◽  
Recrystallization Process ◽  
Full Width ◽  
X Ray Diffraction ◽  
Dramatic Decrease ◽  
X Ray

In situ synchrotron X-ray diffraction was used to study a deformed Cu-0.88 Fe-0.24 P alloy during heating process. The measurements were performed at room temperature and also at high temperatures up to 893 K in order to determine the recovery, ageing and recrystallization process. With the increase of temperature, the angles of copper matrix peaks moved left and the FWHM (full width at half maximum) decreased slightly. Fe3P precipitates were first detected at 533 K, reached the maximum at 673 K, and re-dissolved into matrix at 853 K. A dramatic decrease in FWHM was observed accompanied by the precipitation of Fe3P phases, indicating the reduction of lattice distortion of copper matrix.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

Epitaxial growth of Al(111)/Si(111) films using partially ionized beam deposition

1987 ◽  
Vol 51 (24) ◽  
pp. 1992-1994 ◽  
Author(s):  
C.‐H. Choi ◽  
R. A. Harper ◽  
A. S. Yapsir ◽  
T.‐M. Lu
Keyword(s):  
Epitaxial Growth ◽  
Partially Ionized ◽  
Beam Deposition

In situ high temperature X-ray diffraction study of the kinetics of phase separation in the uranium-plutonium mixed oxide (U0.55Pu0.45)O2-x

2014 ◽  
Vol 1645 ◽  
Author(s):  
Romain VAUCHY ◽  
Renaud.C. BELIN ◽  
Anne-Charlotte ROBISSON ◽  
Fiqiri HODAJ
Keyword(s):  
Phase Separation ◽  
Room Temperature ◽  
Mixed Oxides ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Fundamental Interest ◽  
X Ray ◽  
Uranium Plutonium ◽  
Kinetics Of

ABSTRACTUranium-plutonium mixed oxides incorporating high amounts of plutonium are considered for future nuclear reactors. For plutonium content higher than 20%, a phase separation occurs, depending on the temperature and on the oxygen stoichiometry. This phase separation phenomenon is still not precisely described, especially at high plutonium content. Here, using an original in situ fast X-ray diffraction device dedicated to radioactive materials, we evidenced a phase separation occurring during rapid cooling from 1773 K to room temperature at the rate of 0.05 and 2 K per second for a (U0.55Pu0.45)O2-x compound under a reducing atmosphere. The results show that the cooling rate does not impact the lattice parameters of the obtained phases at room temperature but their fraction. In addition to their obvious fundamental interest, these results are of utmost importance in the prospect of using uranium-plutonium mixed oxides with high plutonium content as nuclear fuels.

scholarly journals Pressure-Induced Dimerization of C60 at Room Temperature as Revealed by an In Situ Spectroscopy Study Using an Infrared Laser

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 182 ◽  
Author(s):  
Bing Li ◽  
Jinbo Zhang ◽  
Zhipeng Yan ◽  
Meina Feng ◽  
Zhenhai Yu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Infrared Laser ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Simple Cubic ◽  
Excitation Laser ◽  
Face Centered ◽  
830 Nm Laser ◽  
Structure Evaluation

Using in situ high-pressure Raman spectroscopy and X-ray diffraction, the polymerization and structure evaluation of C60 were studied up to 16 GPa at room temperature. The use of an 830 nm laser successfully eliminated the photo-polymerization of C60, which has interfered with the pressure effect in previous studies when a laser with a shorter wavelength was used as excitation. It was found that face-centered cubic (fcc) structured C60 transformed into simple cubic (sc) C60 due to the hint of free rotation for the C60 at 0.3 GPa. The pressure-induced dimerization of C60 was found to occur at about 3.2 GPa at room temperature. Our results suggest the benefit and importance of the choice of the infrared laser as the excitation laser.

In situ X-ray diffraction study on epitaxial growth of SixGe1−x on Si by aluminium-assisted crystallization

2017 ◽  
Vol 695 ◽  
pp. 1672-1676 ◽  
Author(s):  
Ziheng Liu ◽  
Xiaojing Hao ◽  
Anita Ho-Baillie ◽  
Martin A. Green
Keyword(s):  
Diffraction Study ◽  
Epitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray

IN SITU SYNTHESIS, CHARACTERIZATION AND FREQUENCY DEPENDENT AC CONDUCTIVITY OF POLYANILINE/CoFe2O4 NANOCOMPOSITES

2011 ◽  
Vol 01 (03) ◽  
pp. 357-362 ◽  
Author(s):  
G. D. PRASANNA ◽  
H. S. JAYANNA
Keyword(s):  
Ac Conductivity ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
In Situ Synthesis ◽  
Electron Micrograph ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Scanning Electron Micrograph ◽  
X Ray

The polyaniline (PANI)/ CoFe2O4 nanocomposites were prepared by an In Situ polymerization of aniline in an aqueous solution. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum,thermogravimetric analysis (TGA) and scanning electron micrograph (SEM). The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz–10 MHz at room temperature. The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt% of CoFe2O4 nanocomposite. At lower frequencies the values of dielectric constant is maximum for pure CoFe2O4 nanoparticles.

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