The advent of graphene has brought science and technology to a new level on the basis of the original. In the near future, it will be applied to the electronic industry, such as CPU, which can make the core speed of CPU reach 300g. Mankind will enter a new era of the electronic industry. Graphene is a single-layer carbon atom surface material stripped from graphite material, a two-dimensional structure of carbon, and a "super material". Its hardness is higher than diamond, and it can stretch like rubber. Its conductivity and thermal conductivity exceed that of any copper wire, and its weight is almost zero. The thickness of this graphite crystal thin film is only 0.335 nm. When 200000 thin films are stacked together, it is only as thick as a human hair.

The extremely thin network material formed by a single layer of carbon atoms has extremely strong thermal and electrical conductivity, which is 100 times stronger than steel with the same thickness. Dr. Andre Geim, 54, of the University of Manchester, UK, and others won the Nobel Prize in physics in 2010 for their research on the method of extracting graphene from graphite. Korean Professor Kim Bili (45 years old), a Korean from Columbia University, is known as one of the world's top experts in this field. Professor Jin was nominated as a co-author in the paper of researcher park.


Samsung Electronics has successfully developed new basic components that can produce chips that are more than 100 times faster than the original semiconductor chips. This is a component made of graphene, a so-called "new material of dreams", which is the research result of the special research institute group of Park Chengjun (41) of Samsung Electronics comprehensive technology institute. This achievement was published in the online edition of science, the world's highest authoritative scientific academic journal, on May 17 (local time), and is expected to be published in the print edition soon.

The gist of the research is "using graphene to make transistors". Graphene transistors are hundreds of times faster than existing semiconductor transistors. This can immediately lead to an increase in the speed of the chip. Chips are made up of billions of tiny transistor arrays.

If graphene is used well, it can be made into faster transistors and chips, which scientists have long paid attention to. Therefore, the world is racing to develop graphene transistors. In this fierce competition, Samsung Electronics Research Group took the lead in beating the song of triumph. This is due to the idea of "attaching semiconductors to graphene". If you want to make a transistor, you need to capture electrons, but inside graphene, this is not an easy thing to do. The "Schottky barrier" is made by combining silicon with graphene. The height of the barrier rises and falls like a dam, so as to achieve continuous and repeated capture and release of electrons. Samsung Electronics named such a transistor "barristor". "Barrier" is a combination of "barrier" and "transistor".

Researcher Park said, "the members of the group have diverse specialties, which can better solve the problems encountered from time to time.". "The power of knowledge integration" is the motive force for the world's first development of graphene transistors. Researcher Park graduated from the Department of chemical engineering of Seoul University and obtained his doctor's degree from Stanford University. The research group of the Institute of integrated technology has seven members, including researcher Park, whose majors are physics and physics? Chemistry? Materials engineering and other fields. "To make graphene chips that can be used in actual electronic devices, we need to go through many stages, such as making smaller transistors, forming integrated circuits on this basis, and then conducting mass production." "we will make unremitting efforts until this goal is achieved.".

Preparation method:

　　GrapheneThere are two main synthetic methods: mechanical method and chemical method. Mechanical methods include micromechanical separation, oriented Epigenesis and SIC heating; Chemical methods are chemical reduction and chemical cleavage.
　　
Micromechanical separation method

The most common is the micromechanical separation method, which directly cuts graphene sheets from larger crystals.

In 2004, novoselovt et al. Prepared single-layer graphene by this method, and it can exist stably in the external environment. A typical preparation method is to expand another material or introduce defective pyrolytic graphite for friction. Floc like crystals will be generated on the surface of bulk graphite, and a single layer of graphene will be contained in these floc like crystals. However, the disadvantage of this method is that it uses the flakes obtained by rubbing the graphite surface to screen out the single-layer graphene flakes. Its size is not easy to control, and it is impossible to reliably produce graphite flakes with sufficient length for application. Oriented epiphytic method crystal film growth oriented epiphytic method is to "seed" graphene by using the atomic structure of the growth matrix. First, carbon atoms are allowed to infiltrate ruthenium at 1150 ℃, and then cooled. After cooling to 850 ℃, a large number of carbon atoms previously absorbed will float to the ruthenium surface. The single-layer carbon atoms "islands" in the shape of lenses cover the whole matrix surface, and eventually they can grow into a complete layer of graphene. After the first layer was covered by 80%, the second layer began to grow. Graphene at the bottom layer will have strong interaction with ruthenium, and after the second layer, it is almost completely separated from ruthenium, leaving only weak electric coupling. The obtained single-layer graphene flakes perform satisfactorily. However, the graphene flakes produced by this method are often uneven in thickness, and the adhesion between graphene and matrix will affect the characteristics of the carbon layer. In addition, the matrix used by Peter W. Sutter and others is rare metal ruthenium.

Heated SiC method

In this method, Si is removed by heating the single crystal 6h SiC, and graphene flakes are decomposed on the (0001) plane of the single crystal. The specific process is as follows: the sample obtained by oxygen or hydrogen etching is heated by electron bombardment under high vacuum to remove oxides. After the oxide on the surface is completely removed by Auger electron spectroscopy, the sample is heated to 1250 ~ 1450 ℃ and then kept constant for 1min ~ 20min to form an extremely thin graphite layer. After several years of exploration, Berger et al. Have been able to controllably prepare single-layer or multi-layer graphene. Its thickness is determined by the heating temperature, so it is difficult to prepare graphene with a single thickness in a large area. Bao Xinhe and others have developed a new way to prepare high-quality free standing graphene materials by high-temperature pyrolysis on a large scale using commercial silicon carbide particles as raw materials. The structure and size of graphene can be controlled by controlling the raw SiC particles, cracking temperature, rate and atmosphere. This is a very novel and important preparation method for the practical application of graphene. 　　

Chemical reduction method

The chemical reduction method is to mix graphite oxide and water at a ratio of 1 mg / ml, vibrate with ultrasonic wave until the solution is clear and free of particulate matter, add an appropriate amount of hydrazine and refluxe at 100 ℃ for 24 hours to produce black particulate precipitation, filter and dry to obtain graphene. Sasha stankovich et al. Prepared graphene with a thickness of about 1 nm by chemical dispersion method. Chemical cleavage method chemical cleavage method is a method of preparing graphene from graphite oxide by thermal reduction. The oxygen-containing functional groups between the graphite oxide layers react at a certain temperature and quickly release gas, so that the graphite oxide layer is cleaved while being reduced to obtain graphene.

This is an important method to prepare graphene. Yang Quanhong of Tianjin University and others prepared high-quality graphene by chemical cleavage of graphite oxide at low temperature& nbsp;& nbsp;