Defects in 4H-SiC Induced by High Energy Helium Implantation

2001 ◽  
Vol 680 ◽  
Author(s):  
Marie F. Beaufort ◽  
Erwan Oliviero ◽  
Marie L. David ◽  
Alain Declémy ◽  
Christian Blanchard ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Amorphous State ◽  
Amorphous Layer ◽  
High Energy ◽  
Helium Implantation ◽  
Buried Layer ◽  
Small Bubbles

ABSTRACT1.6 MeV He+ ions were implanted at room temperature into (0001) 4H-SiC at a dose of 1×1017 cm−2 and then annealed at 1500°C for 30 min. Small bubbles are readily observed in the as-implanted sample but also an amorphous layer. After a 1500°C annealing, recrystallization of the amorphous state occurs and large bubbles or cavities are observed. However their shape strongly depends of their location inside the buried layer. The recrystallization consists of polytypisme, 4H-SiC growth along the c-direction from the substrate, columnar 4H-SiC and epitaxial growth of 3C-SiC.

Silver Nanocrystals at Cavities Created by High Energy Helium Implantation in Bulk Silicon

2007 ◽  
Vol 994 ◽  
Author(s):  
Rachid El Bouayadi ◽  
Gabrielle Regula ◽  
Maryse Lancin ◽  
Eduardo Larios ◽  
Bernard Pichaud ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
Nickel Silicide ◽  
Bulk Silicon ◽  
Shape Characteristic ◽  
Transmission Electron ◽  
Helium Implantation ◽  
Ag Deposition ◽  
First Time ◽  
Good Agreement

AbstractHigh resolution transmission electron microscopy observations show for the first time the presence of two orientations of pure silver precipitates in nanocavities induced in bulk silicon by implantation at 1.6 MeV with a dose of 5×1016 He+ cm−2 and a two hour annealing at 1050°C. These precipitates were called A and B to refer to the two well-known nickel silicide (NiSi2) precipitates or Ag films on a {111} silicon surface. Thus, the A precipitate corresponds to a growth of silver nanocrystal on {111} cavity walls in epitaxy with the Si matrix with an orientation relationship Ag(-111)[211]||Si(-111)[211]. The B precipitate develops on a {111} plane parallel to a {111} cavity wall as well, but in a twin orientation with respect to the Si matrix defined by Ag(-111)[211]||Si(-111)[-2-1-1]. The Ag nanocrystals have a size ranging from a few nm to 50 nm. Most of them have the faceted-shape characteristic of “clean” cavities. They are either A precipitates or they contain alternatively A and B bands in good agreement with both the low stacking fault energy of silver and the two types of nanocrystal orientations obtained by Ag deposition on (111) Si substrate at room temperature. Some Ag precipitates were also found at dislocations located at the He+ projection range, but these trapping sites were found thermally unstable as compared to the cavity ones. Indeed, during a second identical annealing, the precipitates grow in cavities whereas they fade at dislocations.

scholarly journals Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
M. S. Zei
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Lattice Mismatch ◽  
High Energy ◽  
Twin Plane ◽  
Surface Strain ◽  
High Energy Electron ◽  
Direction Parallel ◽  
Plane Normal ◽  
First Time

The epitaxial growth of Pt and Ru deposits by spontaneous, as well as by dynamic, electrodeposition onto Ru(0001) and Pt(111), respectively, have been studied by reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES). For the Pt deposit on Ru(0001), at submonolayer range, it preferably grows compressed commensurate bilayer thick islands on Ru(0001). This is the first time that RHEED observation of the onset of Pt twinning occurs in ca. 2-3 layer thick islands on Ru at room temperature, at which the surface strain due to the 2.5% lattice mismatch of Pt and Ru remains intact. For multilayer thick islands (>6 ML) ordered reflection twins (diameter of 3 nm) develop and are embedded in a (111) matrix with an incoherent (11-2) twin plane normal to Ru(0001) and aligned with their [−110] direction parallel to the [11-20] Ru(0001) substrate direction. For the Ru deposit on Pt(111), at 0.2 ML a strained () monoatomic layer is formed due to the 2.5% lattice mismatch of Ru and Pt. Increasing the coverage up to 0.64, the second Ru layer is found to relieve the strain in the first layer, giving rise to dislocations and Ru relaxes to its bulk lattice constant. Multilayers of Ru (>1 ML) result in (0001) nanocluster formation aligned with its [11-20] direction parallel to the [−110] Pt(111) substrate direction.

scholarly journals Research Progress toward Room Temperature Sodium Sulfur Batteries: A Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1535
Author(s):  
Yanjie Wang ◽  
Yingjie Zhang ◽  
Hongyu Cheng ◽  
Zhicong Ni ◽  
Ying Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Room Temperature ◽  
High Energy ◽  
Safety Performance ◽  
High Energy Density ◽  
Research Progress ◽  
Storage Performance ◽  
Sulfur Battery ◽  
Sodium Sulfur Battery ◽  
Sodium Sulfur

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.

scholarly journals Room‐Temperature Sodium–Sulfur Batteries and Beyond: Realizing Practical High Energy Systems through Anode, Cathode, and Electrolyte Engineering

2021 ◽  
Vol 11 (14) ◽  
pp. 2003493
Author(s):  
Alex Yong Sheng Eng ◽  
Vipin Kumar ◽  
Yiwen Zhang ◽  
Jianmin Luo ◽  
Wenyu Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Energy Systems ◽  
High Energy ◽  
Sodium Sulfur

scholarly journals Monocarborane cluster as a stable fluorine-free calcium battery electrolyte

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazuaki Kisu ◽  
Sangryun Kim ◽  
Takara Shinohara ◽  
Kun Zhao ◽  
Andreas Züttel ◽  
...  
Keyword(s):  
Room Temperature ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
Ionic Conductivities ◽  
High Energy ◽  
High Energy Density ◽  
Free Calcium ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Battery Electrolyte

AbstractHigh-energy-density and low-cost calcium (Ca) batteries have been proposed as ‘beyond-Li-ion’ electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane cluster salt in a mixed solvent as a Ca-battery electrolyte with high anodic stability (up to 4 V vs. Ca2+/Ca), high ionic conductivity (4 mS cm−1), and high Coulombic efficiency for Ca plating/stripping at room temperature. The developed electrolyte is a promising candidate for use in room-temperature rechargeable Ca batteries.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Texture Gradient in ECAP Silver Measured by Synchrotron Radiation

2005 ◽  
Vol 495-497 ◽  
pp. 821-826 ◽  
Author(s):  
Werner Skrotzki ◽  
N. Scheerbaum ◽  
C.G. Oertel ◽  
Heinz Günter Brokmeier ◽  
Satyam Suwas ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Neutron Diffraction ◽  
Room Temperature ◽  
Extrusion Direction ◽  
High Energy ◽  
Texture Gradient ◽  
Fcc Metals ◽  
Local Texture ◽  
Angular Pressing ◽  
Global And Local

Silver of 3N purity was deformed at room temperature by equal channel angular pressing (ECAP) using three passes of route A. The global and local texture were investigated by neutron diffraction and high-energy synchrotron radiation, respectively. The texture is characterized by typical simple shear components of fcc metals which differently deviate from their ideal positions. Local texture measurements reveal that the intensity and inclination of the texture components with respect to the extrusion direction depend on the distance from the top of the extruded bar and change from pass to pass. Reasons for the texture gradient are discussed. The texture of silver is compared with that of copper having a higher stacking fault energy.

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