Researchers have created the first graphene-synthesis method that uses carbon monoxide for carbon. This method is fast and inexpensive and can be used in electronic circuits as well as gas sensors and optics. Researchers from Skolkovo Institute of Science and Technology, Moscow Institute of Physics and Technology, the RAS Institute of Solid State Physics and Aalto University published the study in the prestigious journal Advanced Science.
Chemical vapor deposition is the most common technology to synthesize graphene. It’s a one-atom thick sheet of carbon atoms that are arranged in a honeycomb structure with remarkable properties. This arrangement is ideal for electronics applications. CVD involves carbon atoms separating gas molecules from settling on a substrate in a vacuum chamber as a monolayer. Copper is a very popular substrate. The gases used in CVD are hydrocarbons such as methane, propane and acetylene. Since almost twenty years, we have worked with carbon monoxide. Our first attempts with graphene proved unsuccessful and it took us many years to figure out how to control graphene’s nucleation and growth. “The beauty of carbon monoxide lies in its exclusive catalytic decomposition. This allowed us to implement self limiting synthesis large crystals single-layer graphene even under ambient pressure,” says Albert Nasibulin, principal investigator at Skoltech. This is a brilliant example of how fundamental research can benefit applied technologies. Thanks to a deep understanding of graphene growth and formation, the optimal conditions for the formation of large graphene crystals were possible,” Senior Research Scientist Dmitry Krasnikov from Skoltech stresses.
This new method is based on the principle of self-limiting. When carbon monoxide molecules come within close proximity of the copper substrate, they tend to separate into oxygen and carbon atoms at high temperatures. Once the first layer is formed, the tendency to separate the gas from substrates subsides. This naturally favors the formation a monolayer. However, methane-based CVD may also be self-limiting but in a smaller extent.
“The graphene resulting from the system we used has many advantages. It is purer, faster growing, and forms better crystals,” says Artem Grebenko, Skoltech intern. This tweak also prevents accidents with hydrogen or other explosive gases by eliminating them altogether from the process,” Artem Grebenko, a Skoltech intern, said.
Because the method does not allow for combustion, there is no need to create a vacuum. This apparatus operates at standard pressure making it simpler than traditional CVD equipment. This simplified design allows for faster synthesis. Grebenko claims that it takes only 30 minutes to take a piece of copper and pull out the graphene.
Vacuum is no longer required, making the equipment more efficient and also cheaper. The researcher emphasizes that once you have dropped the expensive hardware required to generate ultrahigh vacuum, it is possible to assemble your ‘garage solution for as little as $1,000.”
Boris Gorshunov (study co-author) at MIPT emphasizes the quality of the resulting graphene: “Whenever a new technique for graphene synthesis is presented, it’s imperative that the researchers show that it produces the results they promise.” We are confident that our graphene is high-quality and can be used in electronics. The resultant material is crystal clear and pure. It can also be used in electronics.
There are many interesting ways graphene can be used in addition to its standard uses. Carbon monoxide is able to stick very well to metal, compared with methane. This means that graphene, which is formed during deposition, both protects the copper layer against chemical reactions and gives it structure. It creates a highly developed metal surface with great catalytic capabilities. Other metals such as palladium and ruthenium would also be useful in this situation to create novel materials with unique surfaces.