Colored O-Rings,Flashlight Silicone O-Ring,Mechanical O-Rings Xlong Seal Co., Ltd. , http://www.xmseals.com
US researchers improve graphene single crystal manufacturing
Researchers at Purdue University in the United States have developed a manufacturing method that can improve the graphene single crystal array to achieve a similar approach and quality to silicon production. "Graphite is not yet in place from the viewpoint of high-quality products realized by silicon crystal, but the progress of this research is a very important step on the road to this development direction." Purdue University Nanoscience and Yong P. Chen, an assistant professor of physics, said. The researchers used chemical vapor deposition to grow hexagonal single crystals from graphene "seeds" on copper foil in a gas chamber containing methane. “Using these seeds, we can grow thousands of very regular graphene single crystal arrays,†says JingkaiYu. Qingkai Yu was the first to use this research method when he was a researcher at the University of Houston. He is now a co-author of the research project and an assistant professor at the Ingram School of Engineering at Texas State University. “We hope that the industry will be able to take note of these new discoveries and consider the ordered array as a possible way to make electronic components.†Graphene is currently fabricated on polycrystalline plates, but this polycrystalline plate is made up of random The "grains" that are placed and irregularly shaped are combined. Conversely, using a more regular ordered array can make the position of each crystal more predictable. These arrays enable researchers to pinpoint electronic components in every die, says Eric Stach, a researcher at Brookhaven National Laboratory in the United States, who was a professor of materials engineering at Purdue University. This new study confirms the theory that when a grain touches another grain, the electron flow will be blocked. This problem can be eliminated by a single crystal grain array. Researchers say they can control the growth of this ordered array, and this is the first time to show the electronic properties of individual grain boundaries—they found that the edges of a single hexagonal grain in a graphene atomic lattice have a clear Parallel directions, thus enabling further finding the direction of each crystal. The researchers used transmission electron microscopy and scanning tunneling microscopy to determine the orientation of the graphene lattice and measured the electronic properties at the grain boundaries using microelectrodes connected to two adjacent grains. The results of the investigation also use Raman spectroscopy to show that there is a higher resistance in the grain boundary, and it also shows that the electrons have scattering properties, so that their conductivity is blocked by the boundary.