Effects on the amorphous Ga2O3 film surfaces by sub-IB-metal-nano-layers

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 285-292
Author(s):  
L. I. Juárez-Amador ◽  
M. Galván-Arellano ◽  
Y. M. Hernández-Rodríguez ◽  
J. A. Andraca-Adame ◽  
G. Romero-Paredes ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rf Sputtering ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Amorphous Films ◽  
X Ray ◽  
Plasmon Frequency ◽  
First Time ◽  
Amorphous Character

AbstractThis work reports by the first time a method to control the geometry of Ga2O3 films nanocrystallites at 350 °C. The formation of controlled shaped nano-crystallites of γ-Ga2O3 from amorphous Ga2O3 films grown by RF-Sputtering at room temperature driven by nano-layers of group IB metals (Cu, Ag or Au) is studied. The reported results can be explained by the role of subsurface metal nano-layers and the non-equilibrium nature of the sputtering processes. To study the effects on the surface structure and their optical properties arrays of amorphous-Ga2O3/IB-metal/amorphous-Ga2O3 were annealed in dry N2 atmosphere at 350 °C by 50, 100 and 150 min. The experimental results can be explained by the evolution of the amorphous character of the films amorphous films towards the nanocrystalline γ-Ga2O3 phase driven by the metal nano-layer seed nature. As the annealing time was increased the transition from amorphous-Ga2O3 to the nanocrystalline γ-Ga2O3 phase was detected by X-ray diffraction analysis. The transition to the nanocrystalline γ-Ga2O3 is demonstrated by the formation of octahedral, triangle and ball shape nanocrystallites with sizes of ∼5 to 50 nm according to FE-SEM analysis. The influence of the metal nano-layer is clearly seen by the shift of the plasmon frequency resonance produced by the Ga2O3/IB-metal/Ga2O3 arrays in the region from 400 to 600 nm caused by the modification of the interface Ga2O3/IB-metal produced by the applied annealing stages.

scholarly journals Physical Stability and Viscoelastic Properties of Co-Amorphous Ezetimibe/Simvastatin System

2019 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Justyna Knapik-Kowalczuk ◽  
Krzysztof Chmiel ◽  
Karolina Jurkiewicz ◽  
Natália Correia ◽  
Wiesław Sawicki ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Viscoelastic Properties ◽  
Room Temperature ◽  
Physical Stability ◽  
Ternary Systems ◽  
Storage Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Conditions ◽  
First Time

The purpose of this paper is to examine the physical stability as well as viscoelastic properties of the binary amorphous ezetimibe–simvastatin system. According to our knowledge, this is the first time that such an amorphous composition is prepared and investigated. The tendency toward re-crystallization of the amorphous ezetimibe–simvastatin system, at both standard storage and elevated temperature conditions, have been studied by means of X-ray diffraction (XRD). Our investigations have revealed that simvastatin remarkably improves the physical stability of ezetimibe, despite the fact that it works as a plasticizer. Pure amorphous ezetimibe, when stored at room temperature, begins to re-crystallize after 14 days after amorphization. On the other hand, the ezetimibe-simvastatin binary mixture (at the same storage conditions) is physically stable for at least 1 year. However, the devitrification of the binary amorphous composition was observed at elevated temperature conditions (T = 373 K). Therefore, we used a third compound to hinder the re-crystallization. Finally, both the physical stability as well as viscoelastic properties of the ternary systems containing different concentrations of the latter component have been thoroughly investigated.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

scholarly journals Chlorosubstituted Copper Phthalocyanines: Spectral Study and Structure of Thin Films

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1620 ◽  
Author(s):  
Alexandr Sukhikh ◽  
Dmitry Bonegardt ◽  
Darya Klyamer ◽  
Pavel Krasnov ◽  
Tamara Basova
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Substrate Surface ◽  
X Ray Diffraction ◽  
Amorphous Films ◽  
X Ray ◽  
Disordered Films ◽  
Copper Phthalocyanines ◽  
First Time ◽  
Ir And Raman

In this work, the tetra-, octa- and hexadecachloro-substituted copper phthalocyanines CuPcClx (where x can equal 4, 8 or 16) were investigated by the methods of vibrational (IR and Raman) spectroscopy and X-ray diffraction. The assignment of the most intense bands, both in IR and Raman spectra, was carried out on the basis of DFT calculations. The structure of a CuPcCl4 single crystal grown by sublimation in vacuum was refined for the first time. The effect of chloro-substitution on the structure of CuPcClx thin films deposited in a vacuum onto a glass substrate at 50 and 200 °C was studied. It was shown that CuPcCl4 formed polycrystalline films with the preferential orientation of the (100) crystallographic plane of crystallites parallel to the substrate surface when deposited on a substrate at 50 °C. Introduction of more Cl-substituents into the phthalocyanine macrocycle leads to the formation of amorphous films on the substrates at 50 °C. At the elevated substrate temperature, the growth of polycrystalline disordered films was observed for all three copper phthalocyanines.

MBE-Grown GaNAsBi Matched to GaAs with 1.3-μm Emission Wavelength

2004 ◽  
Vol 829 ◽  
Author(s):  
Masahiro Yoshimoto ◽  
Wei Huang ◽  
Kunishige Oe
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Laser Diodes ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Peak Energy ◽  
First Time ◽  
Lattice Matched

ABSTRACTGaNyAs1-x-yBix alloy lattice-matched to GaAs has been grown by molecular beam epitaxy (MBE). The lattice-matching of GaNyAs1-x-yBix to GaAs was investigated by X-ray diffraction measurements on a series of GaNyAs1-x-yBix with various GaN molar fractions. GaNyAs1-x-yBix lattice-matched to GaAs was obtained, which was confirmed by its diffraction peak overlapped with the peak of GaAs. Photoluminescence (PL) of 1.3 μm was observed from GaNyAs1-x-yBix epilayer matched to GaAs at room temperature. The temperature coefficient of the PL peak energy in a temperature range 150–300K for GaNyAs1-x-yBix was 1/3 of InGaAsP with a bandgap corresponding to 1.3-μm emission. Both lattice-matching to GaAs and bandgap adjustment to 1.3-μm waveband were achieved for GaNyAs1-x-yBix for the first time. This alloy will lead to the fabrication of laser diodes with an emission of temperature insensitive wavelength.

Mineralogy and formation of evaporite deposits from the Lewis Cliff ice tongue, Antarctica

2014 ◽  
Vol 27 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Tingting Liu ◽  
David L. Bish ◽  
Richard A. Socki ◽  
Ralph P. Harvey ◽  
Eric Tonui
Keyword(s):  
Room Temperature ◽  
Precipitation Process ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
Sulfate Ions ◽  
X Ray ◽  
Bodies Of Water ◽  
Evaporite Minerals ◽  
Glacial Tills ◽  
First Time

AbstractThe mineralogy of evaporites from the Lewis Cliff ice tongue (LCIT), Antarctica, and their mineral stabilities and transformation behaviours under different temperature and relative humidity (RH) conditions have been evaluated to elucidate formation mechanism(s). A variety of sodium (Na)-rich evaporite minerals were documented using RH-controlled powder X-ray diffraction (XRD) methods including Na-sulfates (mirabilite and thenardite), Na-carbonate/bicarbonates (nahcolite, occasional trona and natron) and Na-borates (qilianshanite and borax). Mirabilite begins to dehydrate to thenardite, and natron to trona and natrite when exposed to room temperature, even when maintained at RH values similar to those measured at the LCIT (50–70%). The boron-mineral qilianshanite was discovered for the first time in Antarctica within the evaporite mounds. The mirabilite-rich mounds are deduced to have formed via a freezing/sublimation process that occurred in glacial or subglacial bodies of water supplied by glacial tills containing microbially oxidized sulfate ions. The needle-like nahcolite crystals growing on the exteriors of the mounds suggest a dissolution/precipitation process involving atmospheric CO2 and water. The co-existence of nahcolite and boron-bearing minerals indicates the presence of a Na+-, HCO3-- and boron-bearing alkaline brine, which produces qilianshanite as a secondary mineral by reaction of nahcolite and borax in atmospheric CO2 and H2O.

Growth Morphologies, Fragmentation Patterns, and Hardness in Sodium Hydrogen Urate Monohydrate

2015 ◽  
Vol 1721 ◽  
Author(s):  
A. B. Brune ◽  
W.T. Petuskey
Keyword(s):  
Morphological Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sodium Hydrogen ◽  
Dislocation Arrays ◽  
Fragmentation Patterns ◽  
Microscopy Techniques ◽  
First Time

ABSTRACTMechanical properties and new morphological data on synthetic sodium hydrogen urate monohydrate are reported and interpreted. Crystals formed in supersaturated aqueous solutions were identified by powder x-ray diffraction. Intact grains and separate needles were examined by several microscopy techniques, some reported here for the first time. The dominant morphology was spherulite-type, comprising tapered, branched blades (needles) radiating out of a common core. The pointed blade tips were truncated by (011) planes, corresponding to hydrogen-bonded planes. Branching was at about a 5° angle or its multiples, suggesting it accommodated by dislocation arrays at the low angle boundaries, as is often seen in twinning. Vicker’s micro-hardness, extrapolated to zero porosity, was 0.90 GPa, which is greater than the hardness measured by nano-indentation. Present results are anticipated to be useful in interpreting the mechanical characteristics of the material crystallized in vivo and its action concerning gout, and affording inferences on the role of the milieu on morphologies, fragmentation, and hardness.

Effect of thermal annealing in a-InxGa1–xN films prepared by reactive RF-sputtering

2014 ◽  
Vol 92 (7/8) ◽  
pp. 943-946 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Ruichi Katayama ◽  
Shun Hibino ◽  
Yoshinori Kato ◽  
Fumitaka Ohashi ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Rf Sputtering ◽  
Large Change ◽  
Dark Conductivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Diffraction Patterns ◽  
Composition Ratios

We deposited amorphous indium gallium nitride (a-InxGa1–xN) films at room temperature by reactive radio frequency sputtering with GaN and InN targets and investigated the change of their properties from thermal annealing at annealing temperatures, Ta, below 200 °C. A large change in the indium and nitrogen composition ratios was not observed by thermal annealing at a Ta below 200 °C. In the X-ray diffraction patterns of the films annealed at a Ta below 200 °C, no perceivable peaks assigned to crystalline InxGa1–xN were found. The photoconductivty, σp, increased with an increase in Ta. On the other hand, the increase of the dark conductivity, σd, was very small with an increase in Ta below 200 °C. As a result, the photosensitivity, σp/σd, increased from 252 to 2500 by thermal annealing at a Ta of 200 °C.

Synthesis and Characterisation of Controllable Hairy-PANI Nanofibers with Perchloric Acid

2012 ◽  
Vol 184-185 ◽  
pp. 1280-1284
Author(s):  
Hai Yan Wang ◽  
Xuan Xuan Zhang ◽  
Liang Wei ◽  
Min Jing Zhen ◽  
Lin Bing Kong
Keyword(s):  
Electron Microscopy ◽  
Perchloric Acid ◽  
Room Temperature ◽  
Chemical Oxidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Oxidation Polymerization ◽  
Later Phase ◽  
Amorphous Character ◽  
Scanning Electron

Shape-controllable polyaniline (PANI) nanostructures varying from fibers to hairy-PANI were synthesized via chemical oxidation polymerization with perchloric acid as dopant. It has been achieved just by adding extra aniline in the later phase of the same reaction or by adjusting reactive temperature. The diameters of the hairy-PANI fibers can be controlled to 300nm. Scanning electron microscopy was applied to investigate various kinds of morphologies. The mechanism of forming hairy-fiber morphologies was proposed to the mole ratio of aniline to APS in the later polymerization phase. X-ray diffraction pattern suggested that PANI were an amorphous character. Conductivity of polyaniline synthesized at room temperature was only 10-1 S cm−1 level. The specific surfacearea of the hairy- fibers PANI is more than that of fibers PANI.

RF-Magnetron Sputtered Strontium Titanate: Structure, Processing and Property Relationships

1999 ◽  
Vol 603 ◽  
Author(s):  
B.J. Gibbons ◽  
Y. Fan ◽  
A.T. Findikoglu ◽  
D.W. Reagor ◽  
Q.X. Jia
Keyword(s):  
Room Temperature ◽  
Low Frequency ◽  
Ozone Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treated Sample ◽  
Diffraction Peaks ◽  
Compositional Variations ◽  
First Time

AbstractThe low frequency dielectric properties of epitaxial SrTiO3 thin films deposited on LaAlO3 are presented. The films were deposited using radio-frequency magnetron sputtering from stoichiometric targets in an Ar/O2 atmosphere. For the first time, the effects of in situ ozone annealing during the early stages of deposition were explored. X-ray diffraction results indicated that the ozone treatment resulted in more symmetric and sharper diffraction peaks (2 Θ- FWHM decreased from 0.17° to 0.10°). In addition, the peaks for the ozone treated samples were shifted in 2 Θ towards values approaching the bulk value. Rutherford backscattering measurements showed Sr/Ti ratios of 1:1 for these samples, indicating these peak shifts are not due to compositional variations. The dielectric constant of the ozone treated samples increased from 275 at room temperature to 1175 at 22 K (measured at 100 kHz). The effective loss tangent of the device remained between 1 × 10−4 and 1 × 10−3 down to 100 K, where it began to increase. The tunability was also measured. The ozone treated sample showed tunability of 46%, 43% and 38% at 22 K, 40 K and 60 K, respectively. Finally, similar measurements were completed at 1 MHz, indicating a minimal dependence of these properties on frequencies in this range.

scholarly journals Synthesis and Electrochemical Examination of Fe2O3/CeO2 Nanocomposite for Supercapacitor Application

2019 ◽  
Vol 9 (1S3) ◽  
pp. 379-382
Keyword(s):  
Room Temperature ◽  
Functional Group ◽  
Chemical Precipitation ◽  
Sem Analysis ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supercapacitor Application ◽  
Ftir Technique ◽  
Maximum Specific Capacitance

Fe2O3 /CeO2 nanocomposite was synthesized by a chemical precipitation method in room temperature. The prepared nanocomposite has been subjected to some characterization techniques such as XRD, SEM, FTIR, CV, etc., The presence of crystalline phases of CeO2 and Fe2O3 were confirmed by the powder X–Ray diffraction analysis. Surface morphology of the prepared nanocomposite has been analyzed using SEM analysis. The functional group vibrations were analyzed by FTIR technique. The maximum specific capacitance achieved by using 1M KOH electrolyte solution is about 242 Fg-1 at 5 Ag-1 current density.

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