GaxIn1-xP/GaP Heterostructures on Si(001) Substrate

1996 ◽  
Vol 441 ◽  
Author(s):  
N. Sukidi ◽  
N. Dietz ◽  
U. Rossow ◽  
K. J. Bachmann
Keyword(s):  
Compositional Analysis ◽  
Chemical Beam Epitaxy ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Temperature Growth ◽  
X Ray ◽  
Vegard’S Law ◽  
Graded Interlayer ◽  
Source Materials

AbstractIn this contribution we report on the real-time monitoring of low temperature growth of epitaxial GaxIn1-xP/GaP heterostructures on Si(100) by pulse chemical beam epitaxy, using tertiary butylphosphine (TBP), triethylgallium (TEG), and trimethylindium (TMI) as source materials. Both step-graded and continuously graded heterostructures have been investigated. The composition of the GaxIn1-xP epilayers has been analyzed by various techniques including X-ray diffraction, Rutherford backscattering, Auger, and Raman spectroscopy. Good correlation has been found between X-ray diffraction, RBS, and Vegard's law compositional analysis. We used Ppolarized Reflectance Spectroscopy (PRS) and Laser Light Scattering (LLS) to monitor the growth rate and surface morphology during growth. The information gained by these techniques has been utilized in the improvement of the surface preconditioning as well as to optimize the initial heteroepitaxial nucleation and overgrowth process. We studied the optical response to the compositional changes in the surface reaction layer (SRL) during the exposure of the surface to either sequential or synchronous pulses of TEG and TMI. The cross sectional TEM analysis indicates that the synchronous exposure results in an abrupt GaxIn1-xP/GaP interface while the sequential exposure does not which may suggest a compositionally graded interlayer formation. For heteroepitaxial GaxIn1-xP films on Si, a buffer layer of GaP is found to be necessary for optimum uniformity of the GaxIn1-xP layer. The selective growth of GaxIn1-xP on Si(001) is accessed.

RBS and TEM Analysis of Ta Silicides on GaAs

1983 ◽  
Vol 25 ◽  
Author(s):  
K.L. Kavanagh ◽  
S.H. Chen ◽  
C.J. Palmstrom ◽  
C.B. Carter
Keyword(s):  
Electron Beam ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Cross Sectional ◽  
X Ray ◽  
Sputter Deposited ◽  
Deposited Films

ABSTRACTElectron-beam and sputter-deposited Ta silicides on GaAs were annealed in an As2 overpressure ambient to temperatures as high as 920°C for 20mim. The films were then characterized with RBS, cross-sectional TEM and both electron and x-ray diffraction. The morphology of sputtered TaSi2/GaAs interfaces did not change, however, some interaction was detected at electron-beam deposited GaAs/silicide interfaces. Arsenic in-diffusion was detected at temperatures above 800°C and it was found to be dependent on the stoichiometry of the films. Arsenic diffusion into Si-rich electron-beam and sputter deposited films was low, whereas significantly more As diffused into the Ta-rich silicide. Some indium (3×l015atoms/cm2), from the InAs used as the source of As2overpressure, was observed to accumulate at all GaAs/silicide interfaces at temperatures above 800°C.

Investigation of TiN/TiSi2 Bilayer Thin Films on Si (100) Substrate

1995 ◽  
Vol 402 ◽  
Author(s):  
Y. Shor ◽  
J. Pelleg
Keyword(s):  
Layer Structure ◽  
Reactive Sputtering ◽  
Silicide Formation ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Tin Films ◽  
X Ray ◽  
Resistivity Measurements ◽  
Transmission Electron

AbstractIn this work the conditions of forming a bi – layer structure of TiN/TiSi2 thin film on Si (100) substrate is investigated. Two methods of producing this structure were used: a) Deposition of Ti on Si (100), followed by reactive sputtering to obtain TiN on top of this layer and b) codeposition of Ti and Si on Si (100) and then deposition of TiN by reactive sputtering. The reactive sputtering was carried out in a mixture of N2/Ar with 20% N2. This amount is believed to be optimal for obtaining good quality and stoichiometric TiN films. Annealing is essential to form TiSi2 and it was performed either in the sputtering chamber immediately after the deposition or by rapid thermal annealing (RTA). The structure of the specimens was analyzed by X-ray diffraction using step scanning, Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). TEM analysis was done on cross sectional specimens and also electron diffraction results were recorded. Resistivity measurements were performed by four – point probe method. The influence of TiN on the silicide formation was established. The results indicate that in the presence of TiN the phase TiSi2 was obtained, but in its absence Ti5 Si3 is formed under the same conditions of deposition and annealing. The stress distribution was investigated by Hall – Williamson curves and it was found that TiN stabilizes the silicide film and no peeling was observed. The effectiveness of TiN as diffusion barrier against Al and Si penetration was tested at 500°C/lh. It was found, that under these conditions, the TIN/TiSi2 structure is about the same, as before the heat treatment. No Al penetration is observed.

scholarly journals Multi-Scale Studies of 3D Printed Mn–Na–W/SiO2 Catalyst for Oxidative Coupling of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 290
Author(s):  
Tim Karsten ◽  
Vesna Middelkoop ◽  
Dorota Matras ◽  
Antonis Vamvakeros ◽  
Stephen Poulston ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Oxidative Coupling Of Methane ◽  
Operating Conditions ◽  
Homogeneous Distribution ◽  
Silica Support ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Multi Scale ◽  
3D Printed

This work presents multi-scale approaches to investigate 3D printed structured Mn–Na–W/SiO2 catalysts used for the oxidative coupling of methane (OCM) reaction. The performance of the 3D printed catalysts has been compared to their conventional analogues, packed beds of pellets and powder. The physicochemical properties of the 3D printed catalysts were investigated using scanning electron microscopy, nitrogen adsorption and X-ray diffraction (XRD). Performance and durability tests of the 3D printed catalysts were conducted in the laboratory and in a miniplant under real reaction conditions. In addition, synchrotron-based X-ray diffraction computed tomography technique (XRD-CT) was employed to obtain cross sectional maps at three different positions selected within the 3D printed catalyst body during the OCM reaction. The maps revealed the evolution of catalyst active phases and silica support on spatial and temporal scales within the interiors of the 3D printed catalyst under operating conditions. These results were accompanied with SEM-EDS analysis that indicated a homogeneous distribution of the active catalyst particles across the silica support.

Determination of crystallinity of Chinese handmade papers by means of X-ray diffraction

2020 ◽  
Vol 41 (2) ◽  
pp. 69-86
Author(s):  
Peng Liu ◽  
Hongbin Zhang ◽  
Sinong Wang ◽  
Hui Yu ◽  
Bingjie Lu ◽  
...  
Keyword(s):  
Negative Influence ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Eulaliopsis Binata ◽  
Different Types ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Xrd Method

AbstractThe crystallinity indices (CrI) of Chinese handmade papers were investigated using the X-ray diffraction (XRD) method. Four Chinese handmade papers, Yingchun, Zhuma, Yuanshu and Longxucao papers were used as model substrates of mulberry bark, ramie, bamboo and Eulaliopsis binata papers, respectively. Two forms of the paper samples, paper sheets and their comminuted powders, were used in this study. The results showed that their XRD patterns belong to the cellulose-I type and Iβ dominates the cellulose microstructure of these paper samples. Moreover, it was found that the microstructures and CrIs of cellulose of these papers were changed by the grinding treatment. This work suggested that the sheet form of the handmade papers is suitable to determine CrI by XRD, despite the contribution of non-cellulosic components in the papers. The order of CrIs for these paper sheet samples was Yingchun, Zhuma, Longxucao and Yuanshu papers. Besides CrIs, differences in cross-sectional areas of the crystalline zone of cellulose can be used for comparing different types of handmade papers. It was also found that the CrIs and crystallite size of paper cellulose varied between the sheet samples and the powder samples, illustrating that the pulverisation has a negative influence on the microstructure of the handmade papers.

Surface Morphological Changes of Polyimide with Oxygen Reactive Ion Beam Etching (RIBE)

1988 ◽  
Vol 129 ◽  
Author(s):  
Kyung W. Paik ◽  
Arthur L. Ruoff
Keyword(s):  
Morphological Changes ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Ion Beam Etching ◽  
X Ray ◽  
Disordered Phase ◽  
Beam Incidence ◽  
Yield Difference ◽  
Sectional Plane

ABSTRACTAt the beginning of etching, surface asperities appeared on the top plane of the polyimide (PI) film. The formation of surface asperities is due to the ordered phase in PI film. The known dimension of the ordered phase measured by X-ray diffraction is consistant with the size of surface asperities, 100 Å, observed by TEM. Further ion doses made these asperties evolve into smooth bumps which then eroded into cones as a result of etch yield difference as a function of the angle of beam incidence Y(θ)/Y(0) which has a maximum at θ=70. Finally cones led to the development of grass-likestructure on the top plane of the PI film. The formation of platelike structure on the cross-sectional plane of PI indicates that the structural inhomogeniety of the PI film(the ordered and disordered phase) is the main cause for the surface morphological changes of PI.

scholarly journals Bioactivities of Geranium wallichianum Leaf Extracts Conjugated with Zinc Oxide Nanoparticles

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Banzeer Ahsan Abbasi ◽  
Javed Iqbal ◽  
Riaz Ahmad ◽  
Layiq Zia ◽  
Sobia Kanwal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Energy Dispersive ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Leaf Extracts ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron

This study attempts to obtain and test the bioactivities of leaf extracts from a medicinal plant, Geranium wallichianum (GW), when conjugated with zinc oxide nanoparticles (ZnONPs). The integrity of leaf extract-conjugated ZnONPs (GW-ZnONPs) was confirmed using various techniques, including Ultraviolet–visible spectroscopy, X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, energy-dispersive spectra (EDS), scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The size of ZnONPs was approximately 18 nm, which was determined by TEM analysis. Additionally, the energy-dispersive spectra (EDS) revealed that NPs have zinc in its pure form. Bioactivities of GW-ZnONPs including antimicrobial potentials, cytotoxicity, antioxidative capacities, inhibition potentials against α-amylase, and protein kinases, as well as biocompatibility were intensively tested and confirmed. Altogether, the results revealed that GW-ZnONPs are non-toxic, biocompatible, and have considerable potential in biological applications.

scholarly journals Arizona Salado turquoise: source studies with proton-induced X-ray emission and X-ray diffraction

2013 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Arleyn W. Simon ◽  
Destiny L. Crider ◽  
Tatsuya Murakami ◽  
Barry Wilkens
Keyword(s):  
Source Area ◽  
Xrd Analysis ◽  
American Southwest ◽  
X Ray Diffraction ◽  
X Ray ◽  
Regional Sources ◽  
Platform Mounds ◽  
Complementary Techniques ◽  
Economic Ties ◽  
Source Materials

We compare the composition of turquoise source materials from Arizona to prehistoric blue-green stone artifacts recovered from Salado platform mounds (ca. AD 1275-1450) in the Tonto Basin of Central Arizona. Turquoise samples from known source areas in Arizona including Kingman, Castle Dome, in the Globe- Miami area are compare with others that may have been potential sources of turquoise artifacts recovered from the Salado platform mounds. The complementary techniques of proton-induced X-ray emission (PIXE) for chemical analysis and X-ray diffraction (XRD) for mineralogical signatures are used for nondestructive characterisation of both source area samples and archaeological artifacts. The results of the source area sample characterisations are compared quantitatively with the results of archaeological samples, which are evaluated in terms of their likelihood of being from each of the regional sources. The combination of mineralogical and chemical data to identify source materials provides a more thorough identification of the complex variations within turquoise related materials that may not be distinguished by visual inspection. The PIXE and XRD analysis are compared using a set of multivariate statistics including principal components analysis and discriminant analysis. Additionally, a set of Munsell colour charts specifically for the blue-green range of colours is used to objectively qualify colour in comparison to chemical and mineralogical signatures, as colour alone is not a reliable indicator of composition. The results provide objective data to assess directionality of procurement of turquoise and regional social and economic ties to better understand Salado regional connections during this dynamic period in the American Southwest.

Sol-Gel Synthesis and Characterization of Nanocrystalline Bi4Ti3O12 Powders

2014 ◽  
Vol 997 ◽  
pp. 359-362 ◽  
Author(s):  
Chun Hong Ma ◽  
Xue Lin ◽  
Liang Wang ◽  
Yong Sheng Yan
Keyword(s):  
Phase Inversion ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Synthesis ◽  
Source Materials

Nanocrystalline bismuth titanate (Bi4Ti3O12; BTO) powders were successfully prepared by the sol-gel method, using bismuth nitrate (Bi(NO3)3·5H2O) and tetrabutyl titanate (Ti(OC4H9)4) as source materials, acetic anhydride and ethanediol as solvents. The thermal decomposition and phase inversion process of the gel precursors were studied by using differential thermal analysis (DTA). The crystal structures and microstructures of BTO powders were investigated by using x-ray diffraction (XRD), and transmission electron microscope (TEM). The crystallization of amorphous bismuth titanate has been discussed. The effect of sintering temperature on the structure and morphology of BTO was investigated. At 644 oC and above, BTO powder undergoes a phase transformation from tetragonal to orthorhombic. At 900 oC, the purified orthorhombic BTO nanocrystals were obtained.

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