Growth of 4H-SiC Single Crystals on 6H-SiC Seeds with an Open Backside by PVT Method

2009 ◽  
Vol 615-617 ◽  
pp. 15-18 ◽  
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Katarzyna Racka ◽  
Marcin Raczkiewicz ◽  
Tadeusz Łukasiewicz ◽  
...  
Keyword(s):  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Optical Scanning ◽  
Atomic Force ◽  
The Stability ◽  
Backscatter Diffraction ◽  
Source Materials

4H-SiC single crystals grown by the seeded physical vapour transport method have been investigated. These crystals were grown on 6H-SiC seeds. The influence of the seed temperature, form and granulation of SiC source materials on the stability and efficiency of the 4H polytype growth have been investigated. A new way of the seed mounting - with an open backside - has been used. Crystals obtained were free of structural defects in the form of hexagonal voids. The crystalline structure of SiC crystals was investigated by EBSD (Electron Backscatter Diffraction) and X-Ray diffraction methods. Moreover, defects in crystals and wafers cut from these crystals were examined by optical, scanning electron and atomic force microscopy combined with KOH etching.

scholarly journals Evaluation of grain boundaries as percolation pathways in quartz-rich continental crust using Atomic Force Microscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Continental Crust ◽  
Electron Backscatter Diffraction ◽  
Vital Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Width Measurements ◽  
Lower Temperature ◽  
Backscatter Diffraction

AbstractHydrous fluids play a vital role in the chemical and rheological evolution of ductile, quartz-bearing continental crust, where fluid percolation pathways are controlled by grain boundary domains. In this study, widths of grain boundary domains in seven quartzite samples metamorphosed under varying crustal conditions were investigated using Atomic Force Microscopy (AFM) which allows comparatively easy, high magnification imaging and precise width measurements. It is observed that dynamic recrystallization at higher metamorphic grades is much more efficient at reducing grain boundary widths than at lower temperature conditions. The concept of force-distance spectroscopy, applied to geological samples for the first time, allows qualitative estimation of variations in the strength of grain boundary domains. The strength of grain boundary domains is inferred to be higher in the high grade quartzites, which is supported by Kernel Average Misorientation (KAM) studies using Electron Backscatter Diffraction (EBSD). The results of the study show that quartzites deformed and metamorphosed at higher grades have narrower channels without pores and an abundance of periodically arranged bridges oriented at right angles to the length of the boundary. We conclude that grain boundary domains in quartz-rich rocks are more resistant to fluid percolation in the granulite rather than the greenschist facies.

Temperature-Dependent Mechanical Stability of Retained Austenite in Thermomechanically Processed 3Mn Steel

2021 ◽  
Vol 1016 ◽  
pp. 762-767
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański
Keyword(s):  
Retained Austenite ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Trip Effect ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Static Tensile ◽  
The Stability ◽  
Backscatter Diffraction

The temperature-dependent mechanical stability of retained austenite in medium-Mn transformation induced plasticity 0.17C-3.3Mn-1.6Al-1.7Al-0.22Si-0.23Mo thermomechanically processed steel was investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) methods. Specimens were deformed up to rupture in static tensile tests in a temperature range 20–200°C. It was found that deformation temperature affects significantly the intensity of TRIP effect. In case of specimens deformed at temperatures higher than 60°C, a gradual temperature-related decrease in the stability of γ phase was noted. It indicates a progressive decrease of the significance of the TRIP effect and at the same time the growing importance of the thermally activated processes affecting a thermal stability of retained austenite.

Epitaxial Growth and Characterization of the Ordered Vacancy Compound CuIn3Se5 on GaAs (100) Fabricated by Molecular Beam Epitaxy

1994 ◽  
Vol 340 ◽  
Author(s):  
Art J. Nelson ◽  
M. Bode ◽  
G. Horner ◽  
K. Sinha ◽  
John Moreland
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Symmetric Vibration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTEpitaxial growth of the ordered vacancy compound (OVC) CuIn3Se5 has been achieved on GaAs (100) by molecular beam epitaxy (MBE) from Cu2Se and In2Se3 sources. Electron probe microanalysis and X-ray diffraction have confirmed the composition for the 1-3-5 OVC phase and that the film is single crystal Culn3Se5 (100). Transmission electron microscopy (TEM) characterization of the material also showed it to be single crystalline. Structural defects in the layer consisted mainly of stacking faults. Photoluminescence (PL) measurements performed at 7.5 K indicate that the bandgap is 1.28 eV. Raman spectra reveal a strong polarized peak at 152 cm−1, which is believed to arise from the totally symmetric vibration of the Se atoms in the lattice. Atomic force microscopy reveals faceting in a preferred (100) orientation.

Growth of 6H-SiC Single Crystals under Quasi-Equilibrium Conditions

2008 ◽  
Vol 600-603 ◽  
pp. 15-18
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Władysław Hofman ◽  
Ryszard Diduszko ◽  
Rafał Bożek
Keyword(s):  
Single Crystals ◽  
Quasi Equilibrium ◽  
Vapour Transport ◽  
X Ray Diffraction ◽  
Equilibrium Conditions ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Koh Etching ◽  
Transport Method

Silicon carbide single crystals grown by the seeded physical vapour transport method have been investigated. These crystals were grown on the Si-face (0001) of 6H-SiC seeds. The growth proceeded under quasi-equilibrium conditions with the growth rate in the range 0.05-0.2 mm/h, that was extremely low as compared to used in standard growth processes. The shape and morphology of the crystallization fronts have been studied. Moreover, defects in crystals and wafers cut from these crystals were examined by optical and atomic force microscopy combined with KOH etching and X-Ray diffraction.

scholarly journals The Influence of the Preparation and Stability of Nanofluids for Heat Transfer

2019 ◽  
Vol 25 (4) ◽  
pp. 45-54 ◽  
Author(s):  
Noor Sabih Majeed ◽  
Basma A. Abdulmajeed ◽  
Anwar Khudhur Yaseen
Keyword(s):  
Heat Transfer ◽  
Electron Microscopy ◽  
Base Fluid ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Stability ◽  
Scanning Electron

Recently the use of nanofluids represents very important materials. They are used in different branches like medicine, engineering, power, heat transfer, etc. The stability of nanofluids is an important factor to improve the performance of nanofluids with good results. In this research two types of nanoparticles, TiO2 (titanium oxide) and γ-Al2O3 (gamma aluminum oxide) were used with base fluid water. Two-step method were used to prepare the nanofluids. One concentration 0.003 vol. %, the nanoparticles were examined. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray diffraction (XRD) were used to accomplish these tests. The stability of the two types of nanofluids is measured by zeta potential and UV-vis spectrophotometer. The results showed that γ-Al2O3/water has more stable than TiO2/ water for the same period of time.  

scholarly journals Direct Visualization of Grain Boundaries in Quartzites using Atomic Force Microscopy: Application to Study of Fluid Percolation in Continental Crust

2021 ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Continental Crust ◽  
Electron Backscatter Diffraction ◽  
Vital Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Width Measurements ◽  
Lower Temperature ◽  
Backscatter Diffraction

Abstract Hydrous fluids play a vital role in the chemical and rheological evolution of ductile, quartz-bearing continental crust, where fluid percolation pathways are controlled by grain boundary domains. In this study, widths of grain boundary domains in seven quartzite samples metamorphosed under varying crustal conditions were investigated using Atomic Force Microscopy (AFM) which allows comparatively easy, high magnification imaging and precise width measurements. It is observed that dynamic recrystallization at higher metamorphic grades is much more efficient at reducing grain boundary widths than at lower temperature conditions. The concept of force-distance spectroscopy, applied to geological samples for the first time, allows qualitative estimation of variations in the strength of grain boundary domains. The strength of grain boundary domains is inferred to be higher in the high grade quartzites, which is supported by Kernel Average Misorientation (KAM) studies using Electron Backscatter Diffraction (EBSD). The results of the study show that quartzites deformed and metamorphosed at higher grades have narrower channels without pores and an abundance of periodically arranged bridges oriented at right angles to the length of the boundary. We conclude that grain boundary domains in quartz-rich rocks are more resistant to fluid percolation in the granulite rather than the greenschist facies.

MBE GROWN ZnSSe/ZnMgSSe MQW STRUCTURE FOR BLUE VCSEL

2007 ◽  
Vol 06 (05) ◽  
pp. 407-410 ◽  
Author(s):  
I. P. KAZAKOV ◽  
V. I. KOZLOVSKY ◽  
V. P. MARTOVITSKY ◽  
YA. K. SKASYRSKY ◽  
M. D. TIBERI ◽  
...  
Keyword(s):  
Room Temperature ◽  
Structure Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Optical Scanning ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Two Phases

ZnSSe / ZnMgSSe MQW structures were grown by molecular beam epitaxy on GaAs substrates. The band gap of ZnMgSSe barriers was approximately 3 eV at room temperature. Cathodoluminescence, X-ray diffraction, optical, scanning electron beam, and atomic force microscopy were all used for structure characterization. Decay of the ZnMgSSe solid solution in at least two phases was observed. Improvement in the quality of the crystal lattice and surface morphology was achieved by mismatching the ZnMgSSe from the GaAs substrate by increasing the lattice period by 0.24%.

Optical and Structural Properties of TiO2 Films Deposited from Different Titanium Oxide Materials by Electron Beam

2010 ◽  
Vol 663-665 ◽  
pp. 401-404
Author(s):  
Feng Xiang Wang ◽  
Chang Kwon Hwangbo ◽  
Bu Yong Jung ◽  
Jun He Qi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Near Infrared ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Source Materials ◽  
Deposited Films

TiO2 thin films were deposited from Ti2¬O3, TiO2 and Ti3O5 source materials by e-beam. The refractive index and extinction coefficient of the films in the visible and near infrared（IR） region were measured. The structural and chemical properties of the films were investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). XRD measurements revealed that all the deposited films were amorphous. XPS analysis showed the films were stoichiometric TiO2. The AFM investigation confirmed that the surface roughness of the films was dependent on the deposition conditions.

scholarly journals Structural optical and electrical properties of transparent conductive ITO/Al-Ag/ITO multilayer contact

2019 ◽  
Author(s):  
Aliyu Kabiru Isiyaku ◽  
Ahmad Hadi Ali ◽  
Nafarizal Nayan
Keyword(s):  
Electrical Properties ◽  
Annealing Treatment ◽  
Optical Transmittance ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hall Effect Measurements ◽  
The Stability

Developing a new design and structure of transparent conductive oxides (TCO) materials to improve performance in optoelectronic devices are important and quite challenging. Microstructural, optical and electrical properties of sandwiched Al-Ag metals interlayer between top and bottom ITO layers (ITO/Al-Ag/ITO) have been investigated. The multilayer ITO/Al-Ag/ITO (IAAI) films were prepared using RF and DC magnetron sputtering method. Post annealing treatment at 400oC was conducted on IAAI and ITO (for reference) films in air. X-ray diffraction measurements show that the insertion of Al-Ag intermediate bilayer led to the crystallization of Ag interlayer even at as-deposited stage. Peaks intensities at ITO (222), Ag (111) and Al (200) crystal plane were observed after annealing treatment, indicating an enhancement in crystallinity of the IAAI film. The post-annealed IAAI film reveals a continuous and smooth surface roughness with improved growth in grain size as examined by atomic force microscopy (AFM) and field emission scanning electron microscopic (FESEM) respectively. Comparing the optoelectronic properties of IAAI film with single ITO film, the annealed IAAI film exhibited a remarkable improvement in optical transmittance (86.1%) with a very low sheet resistance of 2.93 Ω/sq as measured by UV-Vis spectrophotometer and four-point probe method. The carrier concentration increased more than double when Al-Ag layer was inserted between the ITO layers as determined by Hall Effect measurements. The under layer Al film helps to halts the Ag film agglomeration and oxidation which subsequently enhances the stability of IAAI multilayer film.  The performance of IAAI contact has been found to be high at 76.4 × 10-3 Ω compares to single ITO (69.4 × 10-3) contact as calculated by the figure of merit (FOM).

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