On Peculiarities of Defect Formation in 6Н-SiC Bulk Single Crystals Grown by PVT Method

2013 ◽  
Vol 740-742 ◽  
pp. 43-47 ◽  
Author(s):  
Gennadi A. Emelchenko ◽  
Andrey A. Zhokhov ◽  
Ilya I. Tartakovskii ◽  
Andrey A. Maksimov ◽  
Edward A. Steinman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Scattering ◽  
Single Crystals ◽  
Formation Mechanism ◽  
Defect Formation ◽  
Structural Defects ◽  
Bulk Single Crystals ◽  
Scanning Electron

The structural defects in the single 6H-SiC crystals grown by the PVT method have been studied by the scanning electron microscopy, Raman scattering and photoluminescence techniques. The formation mechanism of the defects, micropipes and parasitic polytypes 4H and 15R, observed in the single 6H-SiC crystal has been proposed.

Imaging of polymer single crystals in low-voltage, high-resolution scanning electron microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 1106-1107
Author(s):  
W.W. Adams ◽  
G. Price ◽  
A. Krause
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Single Crystals ◽  
Low Voltage ◽  
Polymer Surface ◽  
Beam Current ◽  
Image Features ◽  
First Results ◽  
Scanning Electron

It has been shown that there are numerous advantages in imaging both coated and uncoated polymers in scanning electron microscopy (SEM) at low voltages (LV) from 0.5 to 2.0 keV compared to imaging at conventional voltages of 10 to 20 keV. The disadvantages of LVSEM of degraded resolution and decreased beam current have been overcome with the new generation of field emission gun SEMs. In imaging metal coated polymers in LVSEM beam damage is reduced, contrast is improved, and charging from irregularly shaped features (which may be unevenly coated) is reduced or eliminated. Imaging uncoated polymers in LVSEM allows direct observation of the surface with little or no charging and with no alterations of surface features from the metal coating process required for higher voltage imaging. This is particularly important for high resolution (HR) studies of polymers where it is desired to image features 1 to 10 nm in size. Metal sputter coating techniques produce a 10 - 20 nm film that has its own texture which can obscure topographical features of the original polymer surface. In examining thin, uncoated insulating samples on a conducting substrate at low voltages the effect of sample-beam interactions on image formation and resolution will differ significantly from the effect at higher accelerating voltages. We discuss here sample-beam interactions in single crystals on conducting substrates at low voltages and also present the first results on HRSEM of single crystal morphologies which show some of these effects.

Preparation and Characterisation of TiO2 Thick Films Fabricated by Electrophoretic Deposition

2007 ◽  
Vol 561-565 ◽  
pp. 2163-2166 ◽  
Author(s):  
H.Z. Abdullah ◽  
Charles C. Sorrell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Growth ◽  
Electrophoretic Deposition ◽  
Defect Formation ◽  
Titanium Foil ◽  
X Ray Diffraction ◽  
Voltage Range ◽  
X Ray ◽  
Scanning Electron

Rutile nano-powders were suspended in a solution of acetylacetone and iodine. The suspensions were electrophoretically deposited on titanium foil at a voltage range of 5-30 V over times of 5-120 s. The dried tapes then were sintered at 800°C for 2 h in flowing argon. Both the green and fired tapes were examined by field emission scanning electron microscopy, optical microscopy, X-ray diffraction, and Raman microspectroscopy. The thickness of the films depended on the voltage and the time of deposition. The sintered microstructures depended significantly on the thickness of the film, which was a function the proximity to the Ti/TiO2 interface. The interface is critical to the microstructure because it acts as the source of defect formation, which enhances sintering, grain growth, and grain facetting.

Synthesis of PZT Disks by a Hydrothermal Method

2012 ◽  
Vol 174-177 ◽  
pp. 592-595
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Formation Mechanism ◽  
Powder Diffraction ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
X Ray ◽  
Extended Length ◽  
Scanning Electron

The organization of nanostructures across extended length scales is a key challenge in the design of integrated materials with advanced functions. PbZr0.52Ti0.48O3multilayer disks which were constructed by oriented rectangle nanoparticles were easily prepared by a simple surfactant-free hydrothermal process. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the as-prepared PZT disks were constructed by self-assembly of rectangle nanoparticles by a perfect manner. The formation mechanism of the products was discussed.

Scanning Electron Microscopy Studies of Vacuum Evaporated CdCl2 Doped Cadmium Sulphide Films

2000 ◽  
Vol 6 (S2) ◽  
pp. 454-455
Author(s):  
Ram Kishore ◽  
Venkatram Korapati ◽  
W.D. Brown ◽  
H.A. Naseem
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solar Cell ◽  
Thermal Evaporation ◽  
Cell Structure ◽  
Index Of Refraction ◽  
Structural Defects ◽  
Glass Substrates ◽  
Scanning Electron ◽  
Cds Films

CdTe/CdS thin film solar cells are being investigated extensively these days by many workers as an option for low cost photovoltaic applications . In order to achieve high efficiency solar cell it is important that the CdS film should have minimum possible structural defects and reasonably large grain size. The CdS films for CdTe/ CdS solar cell structure are mostly grown on glass substrates by chemical bath deposition (CBD). Although adherent, transparent and conformal films with index of refraction close to single crystal CdS can be grown by CBD, impurity inclusions and micropinholes are a problem there in. Very little work has been carried out to grow CdS films by thermal evaporation in vacuum. In the present work we have grown pure and CdCl2 doped CdS films on glass substrates by thermal evaporation and carried out microstructural investigations of these films using scanning electron microscopy.Corning 7059 glass of 25.4 x 25.4 x 1.2 mm size were used as substrates for the deposition of CdS as well as CdCl2 doped CdS films.

Laser Pulse Melting of Metals: Epitaxy and Allotropy

1980 ◽  
Vol 1 ◽  
Author(s):  
L. Buene ◽  
E. N. Kaufmann ◽  
C. M. Preece ◽  
C. W. Draper
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Layer ◽  
High Temperature ◽  
Laser Pulse ◽  
Single Crystals ◽  
Laser Power ◽  
Rutherford Backscattering ◽  
Scanning Electron ◽  
Crystallographic Orientations

ABSTRACTLaser pulse melted single crystals of several metals have been examined by the Rutherford backscattering/channeling technique and with optical and scanning electron microscopy. Metals belonging to the three major structure groups; fcc (Ni, Pd, Rh); bcc(Mo, Nb, W, Fe); and hcp (Be, Ti, Re) have been studied at various laser power levels and in different crystallographic orientations. Of these cases, Be, Ti and Fe show high temperature allotropes which are expected to influence the character of the resolidified surface layer.

Polymer-Assisted Hydrothermal Synthesis of PbTiO3 Crystals

2012 ◽  
Vol 528 ◽  
pp. 176-179
Author(s):  
Yong Gang Wang ◽  
Lin Lin Yang ◽  
Xin Wang ◽  
Song Li ◽  
Yu Jiang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Formation Mechanism ◽  
Powder Diffraction ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
X Ray ◽  
Assembly Structure ◽  
Scanning Electron

Using polymer as a surfactant, we successfully synthesized of PbTiO3 crystals with a self-assembly structure by a hydrothermal process. The as-obtained powders were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results show that the presence of PVP, PEG and PVA plays a key role on the formation of self-assembly structure and the corresponding formation mechanism was briefly discussed.

scholarly journals Filmes de diamante CVD em grandes áreas obtidos por crescimentos sucessivos em etapas

2008 ◽  
Vol 13 (3) ◽  
pp. 569-578 ◽  
Author(s):  
A.R. Alves ◽  
A. Amorim ◽  
J. Eichenberger Neto ◽  
V.J. Trava-Airoldi ◽  
E.J. Corat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Raman Scattering ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Raman Scattering Spectroscopy ◽  
Scanning Electron

Buscou-se a redução da tensão intrínseca causada pelas impurezas que se agregam no processo de crescimento de um filme de diamante obtido por deposição química a partir da fase vapor (CVD, do inglês Chemical Vapor Deposition) em um reator de filamento quente (HFCVD), sobre um substrato de silício <100> de 250 µm de espessura em uma superfície de deposição de grande área (45 cm²), através da imersão da amostra, em uma solução saturada de H2SO4 e CrO3 e, em seguida, em uma solução 1:1 de H2O2:NH4OH. Após esse procedimento, nova etapa de crescimento era realizada. O filme de diamante CVD foi identificado e caracterizado por espectroscopia de espalhamento Raman (RSS, do inglês Raman Scattering Spectroscopy) e microscopia eletrônica de varredura (SEM, do inglês Scanning Electron Microscopy). A aplicação dessa técnica mostrou bons resultados, uma vez que, em relação a resultados obtidos anteriormente, se duplicou a espessura do filme de diamante CVD depositado, obtendo menor tensão residual sobre o filme de diamante. Foram obtidos filmes de diamante CVD de espessura de 60 mm, com alta qualidade e uniformidade.

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