Formation of high-density stacking faults in ceramic films induced by Ti transition layer

AbstractLarge lattice mismatch between GaN and α-Al2O3 (15%) leads to the possibility of high threading dislocation densities in the nitride layers grown on sapphire. This investigation focused on defect reduction in GaN epitaxial thin layer was investigated as a function of processing variables. The microstructure changes from threading dislocations normal to the basal plane to stacking faults in the basal plane. The plan-view TEM and the corresponding selected-area diffraction patterns show that the film is single crystal and is aligned with a fixed epitaxial orientation to the substrate. The epitaxial relationship was found to be (0001)GaN∥(0001)Sap and [01-10]GaN∥[-12-10]Sap. This is equivalent to a 30° rotation in the basal (0001) plane. The film is found to contain a high density of stacking faults with average spacing 15 nm terminated by partial dislocations. The density of partial dislocations was estimated from plan-view TEM image to be 7×109 cm−2. The cross-section image of GaN film shows the density of stacking faults is highest in the vicinity of the interface and decreases markedly near the top of the layer. Inverted domain boundaries, which are almost perpendicular to the film surface, are also visible. The concentration of threading dislocation is relatively low (∼;2×108 cm−2), compared to misfit dislocations. The average distance between misfit dislocations was found to be 22 Å. Contrast modulations due to the strain near misfit dislocations are seen in high-resolution cross-sectional TCM micrograph of GaN/α-Al2O3 interface. This interface is sharp and does not contain any transitional layer. The interfacial region has a high density of Shockley and Frank partial dislocations. Mechanism of accommodation of tensile, sequence and tilt disorder through partial dislocation generation is discussed. In order to achieve low concentration of threading dislocations we need to establish favorable conditions for some stacking disorder in thin layers above the film-substrate interface region.

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Growth of SiC Microwires through Si Microwires Carburization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.679-680.512 ◽

2011 ◽

Vol 679-680 ◽

pp. 512-515 ◽

Cited By ~ 1

Author(s):

Maelig Ollivier ◽

Arnaud Mantoux ◽

Edwige Bano ◽

Konstantinos Rogdakis ◽

Konstantinos Zekentes ◽

...

Keyword(s):

Surface Roughness ◽

Raman Spectroscopy ◽

Process Optimization ◽

Gold Catalyst ◽

Stacking Faults ◽

Morphological Characterization ◽

High Density ◽

Silicon Microwires

Silicon microwires (MWs) previously synthesized using the VLS method with gold catalyst are being carburized at 1100°C under methane aiming to their conversion to SiC. SEM, TEM as well as XPS and Raman spectroscopy were used for structural and morphological characterization. After carburization achievement, SiC is found to be polycrystalline with a high density of stacking faults associated to an increase of surface roughness. Directions for the carburization process optimization are given.

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Microstructure Evolution Mechanism of Wf/Cu82Al10Fe4Ni4 Composites under Dynamic Compression at Different Temperatures and Strain Rates

Materials ◽

10.3390/ma14195563 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5563

Author(s):

Zhe Wu ◽

Yang Zhang ◽

Haifeng Jiang ◽

Shuai Zhao ◽

Qingnan Wang

Keyword(s):

Copper Alloy ◽

Split Hopkinson Pressure Bar ◽

Dynamic Compression ◽

Stacking Faults ◽

High Density ◽

Second Phase ◽

Strain Rates ◽

Alloy Matrix ◽

Pressure Infiltration ◽

Different Temperatures

Wf/Cu82Al10Fe4Ni4 composites were fabricated by the pressure infiltration method. The composites were compressed by means of a split Hopkinson pressure bar (SHPB) with strain rates of 800 and 1600 s−1 at different temperatures. The microstructure of the composites after dynamic compressing was analyzed by transmission electron microscopy (TEM). Observation revealed that there were high-density dislocations, stacking faults, twins, and recrystallization existing in the copper alloy matrix of the composites. High-density dislocations, stacking faults, and twins were generated due to the significant plastic deformation of the copper alloy matrix under dynamic load impact. We also found that the precipitated phase of the matrix played a role in the second phase strengthening; recrystallized microstructures of copper alloy were generated due to dynamic recrystallization of the copper alloy matrix under dynamic compression at high temperatures.

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Structural Transformation During the Epitaxial Growth of a System with a Large Misfit: MBE Study of Ni on Au (100)

MRS Proceedings ◽

10.1557/proc-317-621 ◽

1993 ◽

Vol 317 ◽

Cited By ~ 1

Author(s):

B. Gilles ◽

A. Marty ◽

G. Patrat ◽

J.L. Vassent ◽

J.C. Joud ◽

...

Keyword(s):

Epitaxial Growth ◽

Structural Transformation ◽

Stacking Faults ◽

High Density ◽

Interfacial Stress

ABSTRACTThe growth of Ni on Au (100) has been investigated by MBE. It has been found that a Metastable BCT Ni (100) phase is coherent with the substrate up to a thickness of 5 ML. Then a structural transformation analogous to a raartensitic transition occurs, and the structure becomes FCC Ni (110). We show that the interfacial stress is progressively relieved by a high density of stacking faults, as was predicted by Bruinsma and Zangwill for epitaxial overlayers with a large Misfit.

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High-density stacking faults in a supersaturated nitrided layer on austenitic stainless steel

Journal of Applied Crystallography ◽

10.1107/s1600576716014266 ◽

2016 ◽

Vol 49 (6) ◽

pp. 1967-1971 ◽

Cited By ~ 7

Author(s):

Ke Tong ◽

Fei Ye ◽

Honglong Che ◽

Ming Kai Lei ◽

Shu Miao ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Nitrided Layer ◽

Stacking Faults ◽

High Density ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron

The nitrogen-supersaturated phase produced by low-temperature plasma-assisted nitriding of austenitic stainless steel usually contains a high density of stacking faults. However, the stacking fault density observed in previous studies was considerably lower than that determined by fitting the X-ray diffraction pattern. In this work, it has been confirmed by high-resolution transmission electron microscopy that the strip-shaped regions of about 3–25 nm in width observed at relatively low magnification essentially consist of a series of stacking faults on every second {111} atomic plane. A microstructure model of the clustered stacking faults embedded in a face-centred cubic structure was built for these regions. The simulated X-ray diffraction and transmission electron microscopy results based on this model are consistent with the observations.

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Growth of and methanol electro-oxidation by gold nanowires with high density stacking faults

Journal of Materials Chemistry ◽

10.1039/c0jm04083e ◽

2011 ◽

Vol 21 (13) ◽

pp. 4843 ◽

Cited By ~ 30

Author(s):

Yi Lu ◽

Jiang-ping Tu ◽

Chang-dong Gu ◽

Xin-hui Xia ◽

Xiu-li Wang ◽

...

Keyword(s):

Stacking Faults ◽

High Density ◽

Gold Nanowires ◽

Electro Oxidation

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Broadband infrared photoluminescence in silicon nanowires with high density stacking faults

Nanoscale ◽

10.1039/c4nr05410e ◽

2015 ◽

Vol 7 (5) ◽

pp. 1601-1605 ◽

Cited By ~ 12

Author(s):

Yang Li ◽

Zhihong Liu ◽

Xiaoxiang Lu ◽

Zhihua Su ◽

Yanan Wang ◽

...

Keyword(s):

Silicon Nanowires ◽

Stacking Faults ◽

High Density

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Stacking Fault Substructure of Martensite in Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.3493 ◽

2011 ◽

Vol 121-126 ◽

pp. 3493-3497

Author(s):

Yun Ping Ji ◽

Zong Chang Liu ◽

Hui Ping Ren

Keyword(s):

Electron Microscope ◽

Crystal Lattice ◽

Formation Mechanism ◽

Transmission Electron Microscope ◽

Stacking Faults ◽

Stacking Fault ◽

High Density ◽

Shear Mechanism ◽

Transmission Electron

The stacking fault substructure was observed in the quenched martensite of 35CrMo, 2Cr13 and W6Mo5Cr4V2 steels by JEM-2100 transmission electron microscope. It is significant theoretically to discovery the stacking fault substructure and then to study its formation mechanism. The results show that the stacking faults in the martensite of steels are superfine with a few nanometers spacings, which are often concomitant with the high-density dislocations. It is considered that the stacking fault results from the crystal lattice misarrangement during the crystal lattice reconstruction from austenite to martensite in steels. The shear mechanism cannot explain the formation of the stacking fault.

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Effect of Surface Etching Conditions on Stacking Faults in 4H-SiC Epitaxy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.963.119 ◽

2019 ◽

Vol 963 ◽

pp. 119-122

Author(s):

Tawhid Rana ◽

Gil Yong Chung ◽

Steve Anderson ◽

Ian Manning ◽

Willie Bowen ◽

...

Keyword(s):

Stacking Faults ◽

Gas Mixtures ◽

Stacking Fault ◽

High Density ◽

Experimental Results ◽

The Other ◽

Surface Etching ◽

Other Hand ◽

Effect Of Surface

Epilayers grown on substrates etched by various etching conditions were studied for stacking fault defects. Substrates were etched by H2, H2+ HCl and H2 + CxHy gases prior to epilayer growth for comparison. High density of SF was observed in the epilayers when H2+HCl or H2+CxHy gas mixtures were used. On the other hand, much lower density of stacking faults (SF) (<1 cm-2) was observed in the epilayer grown on the surface etched by only H2 gas. However, a high number of pits were generated in the epilayer grown on substrate etched by H2 only, which can be considered to be tradeoff of achieving low SF in epilayer by substrate etching. We also conclude from our experimental results that C rich surface is more favorable to generate SF in epilayer compared to Si rich surface.

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