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Easy technique to manufacture high volumes of graphene, make faster computer chips at lower power

Easy technique to manufacture high volumes of graphene, make faster computer chips at lower power

Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite, as per Wikipedia. It is the strongest material available with superior performance properties such as high electron mobility, which allows the material to be used in next-generation ultra-speed nano-sized instruments. It could revolutionize everything from energy storage to computer chips.
Previous production methods have included things like repeatedly splitting graphite crystals with tape, heating silicon carbide to high temperatures, and various other approaches. Northern Illinois University researchers have developed an easy technique for manufacturing high volumes of graphene. As per the method, pure magnesium metal is burned in dry ice to enable direct conversion of CO2 into few-layer graphene with thickness below 10 atoms. The graphene created consists of several layers (not just one), although it is still less than ten atoms thick. According to Narayan Hosmane, who is the head of the research group, it has already been demonstrated scientifically that burning magnesium metal in CO2 generates carbon. However, the creation of carbon having few-layer graphene as the primary product has neither been discovered nor demonstrated before. Few-layer graphene can be produced in huge quantities using this synthetic method, which is easy, eco-friendly and economical when compared to other processes using tedious techniques and harmful chemicals. The research group originally began the research to produce single-wall carbon nanotubes, but ended up in the production of few-layer graphene.
Future computer chips made out of graphene could be faster than silicon chips and operate at lower power. With the first observation of thermoelectric effects at graphene contacts, University of Illinois researchers found that graphene transistors have a nanoscale cooling effect that reduces their temperature. The speed and size of computer chips are limited by how much heat they dissipate. All electronics dissipate heat as a result of the electrons in the current colliding with the device material, a phenomenon called resistive heating. This heating outweighs other smaller thermoelectric effects that can locally cool a device. Computers with silicon chips use fans or flowing water to cool the transistors, a process that consumes much of the energy required to power a device. Future computer chips made out of graphene� carbon sheets 1 atom thick � could be faster than silicon chips and operate at lower power. However, a thorough understanding of heat generation and distribution in graphene devices has eluded researchers because of the tiny dimensions involved. The Illinois team used an atomic force microscope tip as a temperature probe to make the first nanometer-scale temperature measurements of a working graphene transistor. The measurements revealed surprising temperature phenomena at the points where the graphene transistor touches the metal connections. They found that thermoelectric cooling effects can be stronger at graphene contacts than resistive heating, actually lowering the temperature of the transistor. �In silicon and most materials, the electronic heating is much larger than the self-cooling,� King said. �However, we found that in these graphene transistors, there are regions where the thermoelectric cooling can be larger than the resistive heating, which allows these devices to cool themselves. This self-cooling has not previously been seen for graphene devices.� This self-cooling effect means that graphene -based electronics could require little or no cooling, begetting an even greater energy efficiency and increasing graphene�s attractiveness as a silicon replacement. Next, the researchers plan to use the AFM temperature probe to study heating and cooling in carbon nanotubes and other nanomaterials. The Air Force Office of Scientific Research and the Office of Naval Research supported this work. The team is led by mechanical science and engineering professor William King and electrical and computer engineering professor Eric Pop.
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