The Experts below are selected from a list of 14046 Experts worldwide ranked by ideXlab platform
J. A. Powell - One of the best experts on this subject based on the ideXlab platform.
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threading Dislocation Behavior in aln nucleation layers for gan growth on 4h sic
Applied Physics Letters, 2007Co-Authors: Yoosuf N. Picard, Mark E. Twigg, Michael A. Mastro, C. R. Eddy, R. L. Henry, Ronald T. Holm, P. G. Neudeck, Andrew J. Trunek, J. A. PowellAbstract:Threading Dislocations in thin (<200nm) AlN nucleation layers (NLs) grown by metal-organic chemical vapor deposition on top of 4H-SiC on-axis mesas with atomic-scale steps were analyzed by transmission electron microscopy. The AlN NL controlled threading Dislocations in an overlying ∼2μm GaN layer through two identified mechanisms: threading half-loop formation and Dislocation bending at V-shaped pits. Threading Dislocations in the AlN film could be traced directly to bilayer 4H-SiC steps at the substrate/film interface. These observations reveal several approaches to extended defect reduction in GaN films grown on 4H-SiC.
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Threading Dislocation Behavior in AlN nucleation layers for GaN growth on 4H-SiC
Applied Physics Letters, 2007Co-Authors: Yoosuf N. Picard, Mark E. Twigg, Michael A. Mastro, C. R. Eddy, R. L. Henry, Ronald T. Holm, P. G. Neudeck, Andrew J. Trunek, J. A. PowellAbstract:Threading Dislocations in thin (
Yoosuf N. Picard - One of the best experts on this subject based on the ideXlab platform.
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threading Dislocation Behavior in aln nucleation layers for gan growth on 4h sic
Applied Physics Letters, 2007Co-Authors: Yoosuf N. Picard, Mark E. Twigg, Michael A. Mastro, C. R. Eddy, R. L. Henry, Ronald T. Holm, P. G. Neudeck, Andrew J. Trunek, J. A. PowellAbstract:Threading Dislocations in thin (<200nm) AlN nucleation layers (NLs) grown by metal-organic chemical vapor deposition on top of 4H-SiC on-axis mesas with atomic-scale steps were analyzed by transmission electron microscopy. The AlN NL controlled threading Dislocations in an overlying ∼2μm GaN layer through two identified mechanisms: threading half-loop formation and Dislocation bending at V-shaped pits. Threading Dislocations in the AlN film could be traced directly to bilayer 4H-SiC steps at the substrate/film interface. These observations reveal several approaches to extended defect reduction in GaN films grown on 4H-SiC.
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Threading Dislocation Behavior in AlN nucleation layers for GaN growth on 4H-SiC
Applied Physics Letters, 2007Co-Authors: Yoosuf N. Picard, Mark E. Twigg, Michael A. Mastro, C. R. Eddy, R. L. Henry, Ronald T. Holm, P. G. Neudeck, Andrew J. Trunek, J. A. PowellAbstract:Threading Dislocations in thin (
Takashi Sekiguchi - One of the best experts on this subject based on the ideXlab platform.
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Dislocation Behavior in seed cast grown si ingots based on crystallographic orientation
Progress in Photovoltaics, 2016Co-Authors: Karolin Jiptner, Yoshiji Miyamura, Hirofumi Harada, Bing Gao, Koichi Kakimoto, Takashi SekiguchiAbstract:This study concentrates on Dislocation Behavior during Si growth by the seed-cast method in different crystallographic orientations. Two methods were combined: (1) Si crystal growth in different seed orientations and (2) float zone Si-annealing experiment to obtain the purely thermal stress-induced Dislocation density. The main focus is on the difference between the (111) and the (100) growth directions. It is found that peripheral areas are dominated by thermal stress-induced Dislocation densities. Central ingot areas are dominated by other Dislocation sources. By comparing the (100) and the (111) orientations, it was found that a difference in Dislocation motion exists. This difference is caused by a different activation of slip systems, causing long slip lines in the (111) orientation. It is shown that numerical simulation has problems describing this long-range Dislocation slip. Copyright © 2015 John Wiley & Sons, Ltd.
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Dislocation Behavior in seed‐cast grown Si ingots based on crystallographic orientation
Progress in Photovoltaics: Research and Applications, 2015Co-Authors: Karolin Jiptner, Yoshiji Miyamura, Hirofumi Harada, Bing Gao, Koichi Kakimoto, Takashi SekiguchiAbstract:This study concentrates on Dislocation Behavior during Si growth by the seed-cast method in different crystallographic orientations. Two methods were combined: (1) Si crystal growth in different seed orientations and (2) float zone Si-annealing experiment to obtain the purely thermal stress-induced Dislocation density. The main focus is on the difference between the (111) and the (100) growth directions. It is found that peripheral areas are dominated by thermal stress-induced Dislocation densities. Central ingot areas are dominated by other Dislocation sources. By comparing the (100) and the (111) orientations, it was found that a difference in Dislocation motion exists. This difference is caused by a different activation of slip systems, causing long slip lines in the (111) orientation. It is shown that numerical simulation has problems describing this long-range Dislocation slip. Copyright © 2015 John Wiley & Sons, Ltd.
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Comparison of Dislocation Behavior in Si‐ and C‐face 4H‐SiC
physica status solidi (c), 2011Co-Authors: Bin Chen, Hirofumi Matsuhata, Takashi Sekiguchi, Takasumi Ohyanagi, Akimasa Kinoshita, Hajime OkumuraAbstract:The Dislocation Behavior in C-face 4H-SiC homoepitaxial films was studied by using electron-beam-induced current (EBIC) technique and is compared with that in Si-face ones. For the basal plane Dislocations (BPDs) with the same line shape appearing in the EBIC images, the mobile partial Dislocations (PDs) originated from the dissociation of such BPDs move in two opposite directions, while they move in one direction in the Si-face samples. The difference of the PD movement between two faces is discussed (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Ze Zhang - One of the best experts on this subject based on the ideXlab platform.
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In Situ Observation of Dislocation Behavior in Nanometer Grains
Physical review letters, 2010Co-Authors: Lihua Wang, Xiaodong Han, Pan Liu, Yonghai Yue, Ze ZhangAbstract:Using a newly developed nanoscale deformation device, atomic scale and time-resolved Dislocation dynamics have been captured in situ under a transmission electron microscope during the deformation of a Pt ultrathin film with truly nanometer grains (diameter d < ~10 nm). We demonstrate that Dislocations are highly active even in such tiny grains. For the larger grains (d ~ 10 nm), full Dislocations dominate and their evolution sometimes leads to the formation, destruction, and reformation of Lomer locks. In smaller grains, partial Dislocations generating stacking faults are prevalent.
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in situ observation of Dislocation Behavior in nanometer grains
Physical Review Letters, 2010Co-Authors: Lihua Wang, Xiaodong Han, Pan Liu, Yonghai Yue, Ze ZhangAbstract:Using a newly developed nanoscale deformation device, atomic scale and time-resolved Dislocation dynamics have been captured in situ under a transmission electron microscope during the deformation of a Pt ultrathin film with truly nanometer grains (diameter $dl\ensuremath{\sim}10\text{ }\text{ }\mathrm{nm}$). We demonstrate that Dislocations are highly active even in such tiny grains. For the larger grains ($d\ensuremath{\sim}10\text{ }\text{ }\mathrm{nm}$), full Dislocations dominate and their evolution sometimes leads to the formation, destruction, and reformation of Lomer locks. In smaller grains, partial Dislocations generating stacking faults are prevalent.
Takayuki Sakai - One of the best experts on this subject based on the ideXlab platform.
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In situ transmission electron microscopy observation of Dislocation motion in 9Cr steel at elevated temperatures: influence of shear stress on Dislocation Behavior.
Microscopy (Oxford England), 2014Co-Authors: Susumu Yamada, Takayuki SakaiAbstract:To elucidate high-temperature plastic deformation (creep) mechanism in materials, it is essential to observe Dislocation motion under tensile loading. There are many reports on in situ transmission electron microscopy (TEM) observations in the literature; however, the relationship between the Dislocation motion and shear stress in 9Cr steel is still not clear. In this study, in order to evaluate this relationship quantitatively, in situ TEM observations were carried out in conjunction with finite element method (FEM) analysis. A tensile test sample was strained at an elevated temperature (903 K) inside a transmission electron microscope, and the stress distribution in the strained sample was analyzed by FEM. The Dislocation Behavior was clearly found to depend on the shear stress. At a shear stress of 66 MPa, both the Dislocation velocity and mobile Dislocation density were low. However, a high shear stress level of 95 MPa caused a noticeable increase in the Dislocation velocity and mobile Dislocation density. Furthermore, in this article, we discuss the dependence of the Dislocation Behavior on stress. The results presented here also indicate that the relationship between the microstructure and the strength of materials can be revealed by the methods used in this work.