The researchers proposed the first technique for the synthesis of graphene, which uses carbon monoxide as a carbon source. It is a fast and inexpensive way to produce high quality graphene with relatively simple equipment for use in electronic circuits, gas sensors, optics and more. The study was published in the prestigious journal Advanced Science by researchers from the Skolkovo Institute of Science and Technology (Skoltech), the Moscow Institute of Physics and Technology (MIPT), the RAS Institute for Solid State Physics, Aalto University and others.
Chemical vapor deposition (CVD) is a standard technology for the synthesis of graphene, an atomically thick honeycomb plate in a honeycomb configuration with unrivaled properties useful for applications. in electronics and the like. CVD normally consists of carbon atoms that lack gas molecules and settle on the substrate as a monolayer in a vacuum chamber. Copper is a popular substrate and hydrocarbons are often used as gases: methane, propane, acetylene, spirits and more.
The idea of synthesizing graphene from carbon monoxide has long been lost because this gas is one of the most suitable carbon sources for the growth of single-walled carbon nanotubes. We have almost 20 years of experience working with carbon monoxide. However, our first experiments with graphene were not successful and we have long understood how we can control the nucleation and growth of graphene. The beauty of carbon monoxide lies in its exclusive catalytic decomposition, which allows us to perform a self-limiting synthesis of large single-layer graphene crystals, even at ambient pressure, ”said Albert Nasibulin, principal investigator, Professor Skoltech.
“This project is one of the good examples of how basic research has benefited from the technologies used. Optimized conditions that lead to the formation of large graphene crystals are made possible by understanding the deep kinetic mechanism for graphene cap formation and growth. This is evidenced by theory and experiment, “co-author of the article, Senior Research Scientist Dmitry Krasnikov of Skoltech. The new method benefits from the principle of so-called self-retention of atoms when they are close to a copper substrate. the tendency decreases, so the process apparently promotes monolayer formation. Methane-based CVD can act on its own, but to a lesser extent.
“The system we use has several advantages: The resulting graphene is cleaner, grows faster and becomes better crystals. In addition, this feature prevents accidents with hydrogen and other explosive gases by completely eliminating them from the process,” said Artem Grebenko. first writer Skoltech.
The fact that the method avoids the risks of combustion means that no vacuum is needed. The device works at standard pressure, so it is simpler than a conventional CVD device. Instead, the simplified design leads to faster synthesis. “It only takes 30 minutes to get a bare piece of copper and get graphene,” Grebenko said. Because a vacuum is no longer needed, the device will not only run faster, but can also be cheaper. “Once you install high-quality ultra-high vacuum hardware, you can build our ‘garage solution’ for less than $ 1,000,” said the researcher.
Co-author Boris Gorshunov, a professor at MIPT, emphasized the high quality of the resulting material: “Every time a new graphene synthesis technique is introduced, researchers have to show that it produces what is said. ours is really high quality graphene that can compete with material made from CVD from other gases. ”
In addition to standard applications of graphene as such, there are interesting possibilities of using graphene bound to a copper substrate – without scratching the metal. Carbon monoxide has a very high adhesion to metal compared to methane. This means that when deposition occurs, graphene both protects the copper layer from chemical reactions and gives it structure, resulting in an excellent metal surface with excellent catalytic properties. Other metals, such as ruthenium and palladium, can also be used in this context to open a channel for new materials with unusual surfaces.
