Graphene discovery history
In essence, graphene is isolated, single-atomic layers of flat graphite. According to this theory, scientists have been working with graphene since the creation of X-ray crystallography in the early 20th century. In 1918, V. Kohlschutter and P. Haenni described the properties of graphite oxide paper in detail.In 1948, G. Ruess and F. Vogt published the first images of low-layer graphene (graphene with between 3 and 10 layers) taken by transmission electron microscopy.
Initially, scientists tried to make graphene using the chemical exfoliation method. They inserted large atoms or molecules into graphite to create graphite interlaminar compounds. In its three-dimensional structure, each layer of graphite can be regarded as a monolayer of graphene. After a chemical reaction removes the embedded large atoms or molecules, the result is a pile of graphene slush. Because of the difficulty of analyzing and controlling the physical properties of the sludge, the scientists did not pursue the research. Other scientists use chemical vapor deposition to grow graphene films by epitaxial growth on various substrates, but the initial quality is not good.
In 2004, two physics teams from the University of Manchester and the Institute for Microelectronics Technology in Chernogorovka, Russia worked together to first isolate a single graphene plane. Geim and his team stumbled upon a simple new way to make graphene. They placed sheets of graphite inside the plastic tape, folded the tape around the sides of the sheet, and ripped it open, splitting the sheet in two. By repeating this process, they made thinner and thinner sheets of graphite, some of which consisted of just one layer of carbon atoms -- and they made graphene. Of course, preparation alone is not enough. Normally, graphene is hidden in a pile of graphite residue, rarely sticking to the substrate as desired; So finding experimental quantities of graphene is like looking for a needle in the East China Sea. Even in areas as small as 1 cm2, using the cutting-edge technology of the era, it was impossible to find. Geim's secret is that if graphene is placed on a silicon wafer coated with a certain thickness of silicon oxide. Using the interference effect of light waves, graphene can be found efficiently using a light microscope. This is a very precise experiment; For example, if the thickness of silicon oxide varies by more than 5%, 315nm instead of 300nm, the correct number, monolayer graphene cannot be observed.
Recently, researchers have studied the visibility and contrast of graphene on a variety of substrate materials, and also provided a simple method to enhance visibility. In addition, Raman microscopy for preliminary identification can also increase screening efficiency.
In 2005, the same Manchester team and Columbia University researchers confirmed that graphene's quasiparticles were massless Dirac Fermions. Discoveries like these have sparked a flurry of research into graphene. Since then, hundreds of talented researchers have stepped into this new field.
It is now well known that when graphite is scraped, such as drawing a line with a pencil, tiny fragments of graphene are produced and a large pile of residue is also created. Until 2004/05, no one noticed any use for the debris, so the discovery of graphene should be credited to the Geim team, who discovered a bright new star for solid-state physics.
In the industry, as early as October 2002, the world's first patent on graphene was declared by Dr. Bozeng Zhang, a Chinese-American scientist. The patent content mentioned the composition, production process, and application technology of graphene. In this patent application article, the preparation process of single atomic and multilayer graphene is clearly described. This is believed to be the world's first patent for monolayer graphene, graphene-reinforced metal, resin, carbon, and ceramic matrix composites.
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