Nobel Prize for the discovery of agraphene. How "junk physicists" from Russia won the Nobel Prize
The names of the 2010 Nobel Prize winners in physics have been announced in Stockholm. They were Professor Andrey Geim and Professor Konstantin Novoselov. Both laureates, who work at the British University of Manchester, come from Russia. Andrei Geim, 52, is a citizen of the Netherlands, while Konstantin Novoselov, 36, has Russian and British citizenship.
The most prestigious scientific award in the world, which is about $1.5 million this year, was awarded to scientists for the discovery of graphene, an ultra-thin and extremely durable material, which is a carbon film one atom thick.
About what difficulties arose during the discovery of graphene and what is the practical application of this material, Alexander Sergeev, scientific editor of the Vokrug Sveta magazine, talks on the air of Radio Liberty:
The very fact that scientists have obtained graphene is remarkable. Theoretically, graphene was predicted half a century before its synthesis. At school, everyone went through the structure of graphite - this is an ordinary pencil. The carbon atom forms thin layers that are repeatedly layered on top of each other. Each layer consists of hexagonal cells that, like a honeycomb, dock with each other.
The problem was to get one layer separated from the ones above and below. For a single layer of this two-dimensional crystal, so called because it has no third dimension, a bunch of interesting physical properties have been predicted. There were many experiments. But it was not possible to achieve the separation of one layer from all the others with a stable result.
Andrey Geim and Konstantin Novoselov came up with a way in which they were able to isolate this layer and subsequently make sure that it really is one. The scientists were then able to measure its physical properties and verify that the theoretical predictions were more or less correct. This experiment is very simple: scientists took an ordinary pencil, a piece of graphite. With adhesive tape, a layer of graphite was removed from it, and then they began to peel it off. When 1-2 layers remained, the graphite was transferred onto a silicon substrate.
Why did all previous experiments fail? Because (and this was theoretically predicted) the graphene film, a two-dimensional carbon crystal, is unstable to twisting. As soon as she is in a free state, she will immediately begin to crumple. There was even such an opinion that it was impossible to isolate graphene. The work of scientists was done in 2004, and in 2009 a piece of graphene was already obtained. That is, a sheet of graphene almost a centimeter in size. And now we are talking about tens of centimeters.
Why do we need this graphene at all?
All electronics are now moving in the direction of reducing the size of elements - transistors, electrodes, etc. The smaller the elements inside the processor, the more elements can be placed in it and the more powerful the processor can be assembled. Therefore, more complex logical operations will be performed in it. What can be thinner than one atomic layer? Graphene has the property of thinness.
In addition, it conducts electricity. And it's almost transparent. At the same time, it is strong enough: it is one of the strongest materials per atomic layer. It practically does not pass through itself any other substances. Even gaseous helium cannot seep through graphene, so this is a very reliable coating. It can be used, for example, in touch screens, because the transparent electrode will not obscure the image. You can try to use it in electronics. Now they are trying to develop transistors based on graphenes. True, there are difficulties here. Graphene has anomalous properties that make it somewhat difficult to use in transistors. But after we have learned how to obtain atomic layers, these are probably already surmountable obstacles. This is a fundamentally new material. There has never been anything like it. The thinnest conductor monolayer that can be used in technology, in electronics.
The new Nobel laureates have a rather complicated biography. One of them is a citizen of the Netherlands, the other has two passports: British and Russian. They worked, as far as is known, in the scientific center in Manchester, England. Is science becoming international, or is it the sad fate of Russian scientists to make great discoveries only if they go abroad?
In order to engage in serious scientific work, one needs not only the material and technical base, but also just peace of mind. A scientist should not be confused by some questions. Andrei Game 10 years ago received the Ig Nobel Prize for experiments on the magnetic levitation of frogs. The Ig Nobel Prize is a joke anti-award for meaningless work. A scientist needs a certain freedom in his work. Then ideas are born. Today I levitated frogs, and tomorrow I get graphenes.
If a person has such conditions, then he works more efficiently. After all, both current Nobel laureates in physics studied at the Moscow Institute of Physics and Technology (Moscow Institute of Physics and Technology - RS). And very soon they left for Holland, for Great Britain, because the atmosphere of work there is more favorable for the search for scientific means necessary for conducting research. They tore off the carbon films with adhesive tape, but they had to be measured with an atomic force microscope. So this microscope had to be. In Russia, of course, they are, but they are much more difficult to access.
If I say that Russia has a good basic education that makes it possible to grow Nobel Prize winners, but at the same time there is no serious scientific high-tech base for experiments, would that be true?
As with any generalization, there is some stretch here. With education, we are no longer so good and smooth, because in many places scientific schools are being destroyed. There was a big break in the work of the 90s. There are isolated schools in Russia where everything is still going very well, but there are problems with equipment and conducting serious expensive research. Somewhere this equipment ends up: from time to time, quite serious purchases are made, for example, to the Kurchatov Institute. But how effectively it is applied there is a big question. Therefore, in some places there is a strong scientific school, while in others there are funds for technology. It is quite difficult to exchange them among themselves for reasons of prestige and bureaucracy. In Russia, high-class research is also possible, but it is much more difficult to conduct it - it is a more difficult environment to work here.
Scientific research is multifaceted. But are there separate areas that the Nobel Committee defines as breakthrough? For which it is easier to get a Nobel Prize? Or are there no such directions?
I looked at the list of Nobel Prize winners in physics for the last 20 years. There is no clear trend. There are quite a few awards in the field of elementary particle physics, fundamental physical interactions. This is understandable - they do quite interesting work there. But here we must take into account an important point. It is often said that in order to receive a Nobel Prize, it is not enough to do breakthrough work. We still have to live until the time when it is appreciated. Therefore, the Nobel Prize, as a rule, is awarded to people at a very respectable age. From this point of view, this year's Nobel Prize in Physics is an exception to the rule. Novoselov is now 36 years old. Over the past 20 years, there has not been such a case among the awards in physics, and, in my opinion, there has never been one at all! Over the past 8 years, none of the scientists under 50 years old has received the Nobel Prize, and many received it at the age of 70 or even 80 years old for work done decades ago.
The current Nobel Prize was awarded in violation of the rules. Maybe the Nobel Committee felt that the prize was becoming gerontological and that the age of its receipt should be lowered. The last time at a "young" age the prize in physics was awarded in 2001. The winners were between 40 and 50 years old.
Now, apparently, an installation has been made for actual experimental work. So, although the Nobel Prize does not include astronomy, in the last 10 years there have been two very important prizes in astrophysics. There were awards in high energy physics and elementary particle physics, in solid state physics, in condensed state physics - that is, solid, liquid and other states in which atoms are close to each other. Almost all of these works, one way or another, are tied to quantum physics.
Why exactly quantum theory? Is it due to some personal preferences of the members of the Nobel Committee? Or is it really the nearest scientific future?
The reason is very simple. In fact, all physics, except for the theory of gravity, is now quantum. Almost everything new that is being done in the field of physics, with the exception of certain side directions, improvements and breakthroughs that have been in the past, is based on quantum physics. Only gravity has not yet succumbed to this "quantization". And everything else that concerns the foundation of physics is quantum theory and the quantum theory of matter.
Who is he? Novoselov Konstantin Sergeevich!
Biography
The famous scientist was born in the city of Nizhny Tagil, Sverdlovsk Region, on August 23, 1974, in the family of an engineer and an English teacher at school No. 39, the founder and director of which was once his grandfather, Viktor Konstantinovich Novoselov.
Being in the sixth grade, Konstantin reveals extraordinary abilities and takes first place in the regional physics Olympiad, and a little later, at the All-Union Olympiad, he repeats his success, entering the top ten. In 1991 he graduated from an additional Correspondence School of Physics and Technology and in the same year became a student at the Moscow Institute of Physics and Technology. He studies in the specialty "nanotechnology" at the Faculty of Physical and Quantum Electronics, and graduates with honors from the institute, after which he is hired by IPTM RAS (Institute of Problems of Microelectronics Technology RAS) in Chernogolovka. There he completes postgraduate studies under the guidance of Yuri Dubrovsky.
Abroad
In 1999, Konstantin Sergeevich Novoselov, a physicist with an already established reputation, moved to the Netherlands. There, at the University of Nijmegen, he works with Andre Geim. Since 2001, scientists have been working together at the University of Manchester. In 2004 he received a Ph.D. degree (supervisor Jan-Kees Maan).
At the moment, Konstantin Sergeevich Novoselov is a professor of the Royal Society and a professor of physical and mathematical sciences at the University of Manchester and has dual citizenship (Russia and Great Britain). Now lives in Manchester.
Research
What is Konstantin Sergeevich Novoselov known for? According to the analytical agency Thomson Reuters, the Russian-British physicist is one of the most frequently cited scientists. From his pen came 190 scientific articles. However, his most significant research is, of course, graphene. Many have heard this word, which seems simple and familiar. The technology is really concise and elegant, like all ingenious. Further study is possible, will introduce mankind into the era of ultra-fast and ultra-thin mobile and computer devices, electric cars and durable, but very light structures.
Awards
When Konstantin Sergeevich Novoselov began working at the University of Manchester, a senior colleague from Russia became his leader. By that time, he had been engaged in research in this area for a long time and managed to reproduce the mechanism of sticking of the gecko's paws, and based on it he created an adhesive tape, which physicists later used in work with graphene. Before that, Geim was helped by a certain Chinese student, but, according to the physicist himself, the work began to advance only after Konstantin Sergeevich Novoselov got down to business. The Nobel Prize was awarded to them in October 2010. Novoselov is now known as the youngest Nobel laureate in physics (over the past 37 years), moreover, at the moment he is the only scientist among the Nobel Prize winners who was born after 1970.
In the same 2010, Novoselov received the title of Commander of the Order of the Netherlands Lion for his significant contribution to the science of the Netherlands, and a little later, in 2011, the decree of Queen Elizabeth ll makes him a knight bachelor, already for his contribution to science in Great Britain. The solemn knighting ceremony took place a little later, in the spring of 2012, as expected, at Buckingham Palace. It was hosted by the Queen's daughter, Princess Anne.
It must be said that Konstantin Sergeevich Novoselov, whose scientific and social activities are very extensive, received another prestigious award for graphene research, becoming the winner of the Europhysics Prize in 2008. It is awarded every two years, there were only thirteen Nobel laureates among its prize winners. The award consists of a monetary reward and a corresponding certificate. He also received the Kurti Prize, but not for graphene, but for a list of achievements in working with the sphere of low temperatures and magnetic fields.
About family and life
Konstantin Novoselov is happily married to his wife Irina. Although she is also Russian, scientists met abroad, in the Netherlands. Irina is from Vologda, she is engaged in research in the field of microbiology (she defended her dissertation in St. Petersburg). The couple has two daughters, twins Sofya and Vika, born in 2009.
Konstantin Sergeevich, in his own words, is not the father who sits in the laboratory for weeks, missing the childhood of his own children. For him to invent the smallest transistor in the world and teach his daughter to count to twenty-seven - something that is in the same row. "No one has ever done this before you," he says.
In turn, his parents never tried to limit their son's interests. They were always sure that their son was very gifted, and, as the physicist himself says, they were not surprised when he received the Nobel Prize.
In an interview for Esquire magazine, he admitted that he dreams of learning to play the piano. He is learning, however, by his own admission, the results so far are mediocre.
About the USSR
Konstantin Sergeevich was born in the USSR and received an excellent education. He himself admits that there are few places where you can get such deep knowledge. But he is not going to return to Russia. Perhaps it is precisely because of this that some journalists unwittingly reproach him for his lack of patriotism. To this, the scientist replies that it’s not about money, it’s just that working in Britain is calmer, because no one interferes in your affairs.
Novoselov takes life lightly, does not get hung up on failures - this is one of his basic rules. If difficulties arise in relations with people, he tries not to lead to a break, but, if this is inevitable, he leaves the last word to another person. A famous physicist has many common life problems, for example, he would be ready to spend any money just to get some free time.
But he does not divide his life into work and leisure, perhaps this is the key to the scientist's productivity. At home, he thinks about physics, and at work he just rests his soul.
What is graphene
Despite, of course, all the achievements in the field of physics, Novoselov's main work was and still is graphene. This structure, which was obtained for the first time in the laboratory by our compatriots, is a two-dimensional "grid" of carbon atoms only one atom thick. Novoselov himself claims that the technology is not complicated and anyone can create graphene, almost from improvised means. He says it's enough to get some good graphite to get you started, although you can even use pencils and splurge a bit on silicon wafers and tape. Everything, the set for creating graphene is ready! Thus, the material will not become the property of exclusively large corporations, Novoselov and Game literally donated it to the whole world.
Amazing Properties
The physicist is also surprised by the electronic properties of this material. According to him, graphene can be used in transistors, which is what some companies are already trying to do, replacing familiar parts in mobile devices.
According to Novoselov, graphene will revolutionize technology. An integral part of any science fiction film is incredible gadgets, transparent, thin, unbreakable and with great functionality. If graphene gradually replaces obsolete silicon, technologies from the cinema will appear in life.
What else is remarkable about the studies of Novoselov and Geim? The fact that they almost instantly migrated from laboratories to conveyors, and even more - turned out to be very useful in the early years.
Future technologies
Where is graphene used now? It would seem that such recently discovered material could not yet spread widely, and this is partly true. Almost all developments are still experimental in nature and have not been released into mass production. However, they are now trying to use this material in literally all areas, which, perhaps, can be called a real "graphene fever".
Graphene itself, despite its low weight and almost complete transparency (it absorbs 2% of transmitted light, exactly the same as ordinary window glass), the material is very durable. Recent studies by American scientists have shown that graphene mixes well with plastic. This results in a super-strong material that can be used in everything from furniture and mobile phones to rocket science.
Prototypes of batteries for electric cars have already been created from graphene. They are characterized by high capacity and short charging time. Perhaps this is how the problem with electric vehicles will be solved, and transport will become cheap and environmentally friendly.
Graphene is used in the development of new touch panels for phones. If classical sensors can only work on a flat surface, then graphene is free of this drawback, because it can be bent as you like. In addition, high electrical conductivity will make the response minimal.
In aviation
The bodies of rockets and aircraft made using graphene will be several times lighter, which will greatly reduce fuel costs. Flights will become so cheap that anyone can afford to travel to the other side of the earth. But, in addition to passenger traffic, this will, of course, also affect freight traffic. The supply of remote corners of the planet will become much better, which means that more people will live and work there.
MOSCOW, October 5 - RIA Novosti. The 2010 Nobel Prize in Physics was a celebration for two countries at once, for the homeland of the laureates - Russia, and for their current home - Britain. Swedish academics awarded the highest scientific award to Andrey Geim and Konstantin Novoselov for the discovery of a two-dimensional form of carbon - graphene, forcing Russian scientists to complain about the brain drain, and British scientists - to hope for continued funding for science.
"It's a pity that Geim and Novoselov made their discoveries abroad," Alexei Khokhlov, head of the Department of Polymer and Crystal Physics at Moscow State University, told RIA Novosti.
"The government should learn from the decision of the Nobel Committee," - commented on the award of the Nobel Prize in Physics, the President of the Royal Society of Science, Professor Martin Reese. He recalled that many scientists, including foreign ones, who work in Britain, in the event of a curtailment of funding, can simply leave for other countries.
The British government on October 20 will announce plans for a serious cut in government spending. Science and higher education is expected to be one of the areas most affected by cuts.
MIPT graduates Game and Novoselov, who work in Manchester, received the award "for pioneering experiments on the study of two-dimensional graphene material." They will share 10 million Swedish kronor (about one million euros) among themselves. The award ceremony will take place in Stockholm on December 10, the day of the death of its founder, Alfred Nobel.
Graphene became the first two-dimensional material in history, consisting of a single layer of carbon atoms interconnected by a structure of chemical bonds resembling the structure of a honeycomb in its geometry. For a long time it was believed that such a structure was impossible.
"It was believed that such two-dimensional single-layer crystals could not exist. They must lose stability and turn into something else, because it is actually a plane without thickness," the former head of the laureates, director of the Institute for Problems of Technology of Microelectronics and High-Purity Materials of the Russian Academy of Sciences (IPTM) told RIA Novosti ) Vyacheslav Tulin.
However, the "impossible" material, as it turned out, has unique physical and chemical properties that make it indispensable in various fields. Graphene conducts electricity as well as copper, it can be used to create touch screens, solar cells, flexible electronic devices.
"This is a future revolution in microelectronics. If now computers are gigahertz, then they will be terahertz and so on. Transistors and all other elements of electronic circuits will be created on the basis of graphene," Alexei Fomichev, professor at the MIPT Department of Quantum Electronics, told RIA Novosti.
Graphene has already found one area of application: solar photovoltaic cells. “Previously, tin-doped indium oxides were used as a transparent electrode in the production of photovoltaic cells. But it turned out that several layers of graphene are much more efficient,” said Alexander Vul, head of the laboratory for physics of cluster structures at the St. Petersburg Ioffe Institute of Physics and Technology, Russian Academy of Sciences.
The first from the physics and technology department
Andrei Geim and Konstantin Novoselov are the first ever graduates of the Moscow Institute of Physics and Technology to receive the Nobel Prize: before that, the founders and employees of the Moscow Institute of Physics and Technology - Petr Kapitsa, Nikolai Semenov, Lev Landau, Igor Tamm, Alexander Prokhorov, Nikolai Basov, Vitaly Ginzburg and Alexey Abrikosov. Geim graduated from the Faculty of General and Applied Physics (FOPF) in 1982, Novoselov - from the Faculty of Physical and Quantum Electronics (FFKE) in 1997. Both graduates received red diplomas.
"This is super news. We are very pleased with the decision of the Nobel Committee. MIPT has already sent congratulations to the new Nobel laureates," MIPT Rector Nikolai Kudryavtsev told RIA Novosti on Tuesday.
According to the rector, the staff "raised their personal files from the archive and made sure that they were outstanding students." At the same time, Andrey Geim did not enter the institute the first time, having worked for a year at the plant, but "showed persistence" and became a student at the Moscow Institute of Physics and Technology.
"During the entire time of study at the FOPF, Geim received the highest reviews from teachers. And Geim's final work was rated exceptionally highly by the diploma committee," said the head of the Moscow Institute of Physics and Technology.
A student of the 152nd group of the Faculty of Physical and Quantum Electronics, Konstantin Novoselov, as Kudryavtsev noted, "attended classes irregularly, but handed over all assignments successfully and on time."
"And the teachers' reviews of Novoselov are also the highest. This means that he was so talented that, in general, it was not necessary for him to go to all classes," the rector of the Moscow Institute of Physics and Technology commented on the archival documents.
From Schnobel to Nobel
Geim's colleague, Konstantin Novoselov, became the youngest Nobel laureate with Russian citizenship: the 36-year-old physicist is six years younger than his Soviet colleague Nikolai Basov, who at 42 received the 1964 prize for his work in the field of quantum electronics, which led to the creation of emitters and amplifiers based on the laser-maser principle .
The youngest Nobel Prize winner in history was Lawrence Bragg, who at the age of 25 shared the prize in physics with his father, William Henry Bragg. The next four positions in the list of the youngest laureates in history are also occupied by physicists: Werner Heisenberg, Zongdao Li, Karl Anderson and Paul Dirac received prizes at 31 years old.
Konstantin Novoselov, however, will go down in history as the first member of the generation born in the 1970s. Physicist Eric Cornell, biologists Carol Greider and Craig Mello, and U.S. President Barack Obama, who received the Nobel Peace Prize, represent the previous decade on the list of laureates. There is no one younger than 1961, except for Novoselov, in the list of laureates.
From the editor: Touching upon the topic of modernization of the Russian economy and the development of high technologies in our country, we set the task not only to draw the attention of readers to the shortcomings, but also to talk about positive examples. Moreover, there are, and a lot of them. Last week we talked about the development of fuel cells in Russia, and today we’ll talk about graphene, for the study of the properties of which “our former people” recently received the Nobel Prize. It turns out that in Russia, or rather, in Novosibirsk, they are working on this material very seriously.
Silicon as the basis of microelectronics has firmly won its position in the high-tech space, and this did not happen by chance. First, it is relatively easy to impart the desired properties to silicon. Secondly, it has been known to science for a long time, and has been studied "up and down". The third reason is that truly gigantic funds have been invested in silicon technologies, and few people will dare to bet on a new material now. After all, for this it will be necessary to rebuild a huge industrial sector. Rather, build it almost from scratch.
However, there are other contenders for leadership as a semiconductor material. For example, graphene, which after the Nobel Prize for the study of its properties, has become very fashionable. Indeed, there are reasons to switch to it from silicon, since graphene has a number of significant advantages. But whether we will end up with “graphene-based electronics” is not yet clear, because along with the advantages, there are also disadvantages.
To talk about the prospects of graphene in microelectronics and its unique properties, we met in Novosibirsk with the chief researcher of the Institute of Inorganic Chemistry. A. V. Nikolaev SB RAS, Doctor of Chemical Sciences, Professor Vladimir Fedorov.
Alla Arshinova: Vladimir Efimovich, what are the current positions of silicon in microelectronics?
Vladimir Fedorov: Silicon has been used in the industry as the main semiconductor material for a very long time. The fact is that it is easily doped, that is, atoms of various elements can be added to it, which change the physical and chemical properties in a directed way. Such a modification of high-purity silicon makes it possible to obtain n- or p-type semiconductor materials. Thus, directional doping of silicon regulates the functional properties of materials that are important for microelectronics.
Silicon is a truly unique material, and this is the reason why so much effort, money and intellectual resources have been invested in it. The fundamental properties of silicon have been studied in such detail that there is a widespread opinion that there simply cannot be a replacement for it. However, recent research on graphene has given the green light to another view, which is that new materials can be advanced to the point where they can replace silicon.
Crystal structure of silicon
Such discussions arise periodically in science, and they are resolved, as a rule, only after serious research. For example, recently there was a similar situation with high-temperature superconductors. In 1986, Bednorz and Müller discovered superconductivity in barium-lanthanum-copper oxide (for this discovery they were awarded the Nobel Prize already in 1987 - a year after the discovery!), which was detected at a temperature significantly higher than the values characteristic of the known time of superconducting materials. At the same time, the structure of cuprate superconducting compounds differed significantly from low-temperature superconductors. Then, an avalanche-like study of related systems led to the production of materials with a superconducting transition temperature of 90 K and above. This meant that not expensive and capricious liquid helium could be used as a refrigerant, but liquid nitrogen - there is a lot of it in gaseous form in nature, and besides, it is much cheaper than helium.
But, unfortunately, this euphoria soon passed after careful research of new high-temperature superconductors. These polycrystalline materials, like other complex oxides, are similar to ceramics: they are brittle and non-ductile. It turned out that superconductivity inside each crystal has good parameters, but in compact samples the critical currents are rather low, which is due to weak contacts between grains of the material. Weak Josephson junctions between superconducting grains do not make it possible to fabricate a material (for example, to make a wire) with high superconducting characteristics.
Solar battery based on polycrystalline silicon
The same situation can happen with graphene. At present, very interesting properties have been found for it, but extensive research remains to be done to finally answer the question of the possibility of obtaining this material on an industrial scale and using it in nanoelectronics.
Alla Arshinova: Can you please explain what graphene is and how it differs from graphite?
Vladimir Fedorov: Graphene is a monoatomic layer formed from carbon atoms, which, like graphite, has a honeycomb-shaped lattice. And graphite is, respectively, stacked on top of each other in a pile of graphene layers. Graphene layers in graphite are interconnected by very weak van der Waals bonds, which is why it is possible, in the end, to tear them apart. When we write with a pencil, this is an example of the fact that we are peeling off layers of graphite. True, the trace of a pencil remaining on paper is not yet graphene, but a graphene multilayer structure.
Now every child can say in all seriousness that he does not just translate paper, but creates the most complex graphene multilayer structure.
But if it is possible to split such a structure to a single layer, then true graphene is obtained. Similar splittings were carried out by this year's Nobel laureates in physics Geim and Novoselov. They managed to split the graphite with adhesive tape, and after studying the properties of this “graphite layer”, it turned out that it has very good parameters for use in microelectronics. One of the remarkable properties of graphene is its high electron mobility. They say that graphene will become an indispensable material for computers, phones and other equipment. Why? Because in this area there is a tendency to accelerate the procedures for processing information. These routines are related to the clock frequency. The higher the operating frequency, the more operations can be processed per unit of time. Therefore, the speed of charge carriers is very important. It turned out that charge carriers in graphene behave like relativistic particles with zero effective mass. Such properties of graphene really allow us to hope that it will be possible to create devices capable of operating at terahertz frequencies that are inaccessible to silicon. This is one of the most interesting properties of the material.
Nobel Laureates in Physics 2010 Andrey Geim and Konstantin Novoselov
Flexible and transparent films can be obtained from graphene, which is also very interesting for a number of applications. Another plus is that it is a very simple and very light material, lighter than silicon; besides, there is plenty of carbon in nature. Therefore, if they really find a way to use this material in high technologies, then, of course, it will have good prospects and, possibly, will eventually replace silicon.
But there is one fundamental problem associated with the thermodynamic stability of low-dimensional conductors. As is known, solid bodies are subdivided into various spatial systems; for example, the 3D (three-dimensional) system includes bulk crystals. Two-dimensional (2D) systems are represented by layered crystals. And chain structures belong to a one-dimensional (1D) system. So, low-dimensional - 1D chain and 2D layered structures with metallic properties are not stable from a thermodynamic point of view, as the temperature decreases, they tend to turn into a system that loses metallic properties. These are the so-called metal-insulator transitions. How stable graphene materials will be in some devices remains to be seen. Of course, graphene is interesting, both in terms of electrical and mechanical properties. It is believed that the monolithic layer of graphene is very strong.
Alla Arshinova: Stronger than diamond?
Vladimir Fedorov: Diamond has three-dimensional bonds, mechanically it is very strong. In graphite in the plane, the interatomic bonds are the same, maybe stronger. The fact is that from a thermodynamic point of view, diamond should turn into graphite, because graphite is more stable than diamond. But in chemistry, there are two important factors that control the process of transformation: these are the thermodynamic stability of the phases and the kinetics of the process, that is, the rate of transformation of one phase into another. So, diamonds have been lying in the museums of the world for centuries and they don’t want to turn into graphite, although they should. Maybe in millions of years they will still turn into graphite, although it would be a pity. The process of diamond to graphite at room temperature is very slow, but if you heat the diamond to a high temperature, then the kinetic barrier will be easier to overcome, and this will definitely happen.
Graphite in its original form
Alla Arshinova: The fact that graphite can be split into very thin flakes has long been known. What then was the achievement of the 2010 Nobel laureates in physics?
Vladimir Fedorov: You probably know such a character as Petrik. After the Nobel Prize was awarded to Andrey Geim and Konstantin Novoselov, he stated that the Nobel Prize had been stolen from him. In response, Game said that, indeed, such materials have been known for a very long time, but they were given the prize for studying the properties of graphene, and not for discovering a method for obtaining it as such. In fact, their merit is that they were able to split off very good quality graphene layers from highly oriented graphite and study their properties in detail. The quality of graphene is very important, just like in silicon technology. When they learned how to obtain silicon of a very high degree of purity, only then did electronics based on it become possible. The same is true for graphene. Geim and Novoselov took very pure graphite with perfect layers, managed to split off one layer and studied its properties. They were the first to prove that this material has a set of unique properties.
Alla Arshinova: In connection with the awarding of the Nobel Prize to scientists with Russian roots working abroad, our compatriots who are far from science are wondering if it was possible to come to the same results here in Russia?
Vladimir Fedorov: Probably it was possible. They just left at the right time. Their first paper, published in Nature, was co-authored with several Chernogolovka scientists. Apparently, our Russian researchers also worked in this direction. But it failed to complete it convincingly. It's a pity. Perhaps one of the reasons is more favorable conditions for working in foreign scientific laboratories. I recently arrived from Korea and can compare the working conditions I was given there with working at home. So there I was not concerned about anything, and at home - full of routine duties that take a lot of time and constantly distract from the main thing. I was provided with everything I needed, and it was done with amazing speed. For example, if I need some kind of reagent, I write a note - and the next day they bring it to me. I suspect that the Nobel laureates also have very good working conditions. Well, they had enough perseverance: they repeatedly tried to get good material and finally achieved success. They really spent a lot of time and effort on this, and the award in this sense is well-deserved.
Alla Arshinova: And what exactly are the advantages of graphene compared to silicon?
Vladimir Fedorov: First, we have already said that it has a high mobility of carriers, as physicists say, charge carriers do not have mass. Mass always slows down movement. And in graphene, electrons move in such a way that we can consider them to have no mass. This property is unique: if there are other materials and particles with similar properties, they are extremely rare. Graphene turned out to be good in this, and in this it compares favorably with silicon.
Secondly, graphene has a high thermal conductivity, which is very important for electronic devices. It is very light and the graphene sheet is transparent and flexible and can be rolled up. Graphene can also be very cheap if optimal methods are developed for its production. After all, the "scotch method", which was demonstrated by Game and Novoselov, is not industrial. With this method, samples of really high quality are obtained, but in very small quantities, only for research.
And now chemists are developing other ways to obtain graphene. After all, you need to get large sheets in order to put the production of graphene on stream. We are also dealing with these issues here, at the Institute of Inorganic Chemistry. If graphene can be synthesized using methods that would allow the production of high-quality material on an industrial scale, then there is hope that it will revolutionize microelectronics.
Alla Arshinova: As probably everyone already knows from the media, a graphene multilayer structure can be obtained using a pencil and adhesive tape. And what is the technology for obtaining graphene used in scientific laboratories?
Vladimir Fedorov: There are several methods. One of them has been known for a very long time, it is based on the use of graphite oxide. Its principle is quite simple. Graphite is placed in a solution of highly oxidizing substances (for example, sulfuric, nitric acid, etc.), and when heated, it begins to interact with oxidizing agents. In this case, graphite is split into several leaves or even into monatomic layers. But the resulting monolayers are not graphene, but are oxidized graphene, which has attached oxygen, hydroxyl and carboxyl groups. Now the main task is to restore these layers to graphene. Since small particles are obtained during oxidation, they must somehow be glued together in order to obtain a monolith. The efforts of chemists are aimed at understanding how it is possible to make a graphene sheet from graphite oxide, the production technology of which is known.
There is another method, also quite traditional and known for a long time - this is chemical vapor deposition with the participation of gaseous compounds. Its essence is as follows. First, the reaction substances are sublimated into the gas phase, then they are passed through a substrate heated to high temperatures, on which the desired layers are deposited. When the initial reagent, for example, methane, is selected, it can be decomposed in such a way that hydrogen is split off and carbon remains on the substrate. But these processes are difficult to control, and it is difficult to obtain an ideal layer.
Graphene is one of the allotropic modifications of carbon
There is another method that is now beginning to be actively used - the method of using intercalated compounds. In graphite, as in other layered compounds, molecules of various substances, which are called "guest molecules", can be placed between the layers. Graphite is the "host" matrix where we supply "guests". When guests are intercalated into the host grid, naturally the layers are separated. This is exactly what is required: the intercalation process breaks down the graphite. Intercalated compounds are very good precursors for obtaining graphene - you just need to take out the "guests" from there and prevent the layers from collapsing back into graphite. In this technology, an important step is the process of obtaining colloidal dispersions that can be converted into graphene materials. We support this approach in our institute. In our opinion, this is the most advanced direction, from which very good results are expected, because isolated layers can be obtained most simply and efficiently from various kinds of intercalated compounds.
Graphene is similar in structure to honeycombs. And recently it has become a very "sweet" topic
There is another way, which is called total chemical synthesis. It lies in the fact that the necessary "honeycombs" are assembled from simple organic molecules. Organic chemistry has a very developed synthetic apparatus, which makes it possible to obtain a huge variety of molecules. Therefore, the method of chemical synthesis is trying to obtain graphene structures. So far, it has been possible to create a graphene sheet consisting of about two hundred carbon atoms.
Other approaches to the synthesis of graphene are also being developed. Despite numerous problems, science in this direction is successfully moving forward. There is a great deal of confidence that the existing obstacles will be overcome, and graphene will bring a new milestone in the development of high technologies.
PhD in Chemistry Tatyana Zimina.
The 2010 Nobel Prize in Physics was awarded for research on graphene, a two-dimensional material that exhibits unusual and at the same time very useful properties. Its discovery promises not only new technologies, but also the development of fundamental physics, which may result in new knowledge about the structure of matter. This year's Nobel Prize winners in physics are Andre Game and Konstantin Novoselov, professors at the University of Manchester (Great Britain), graduates of the Moscow Institute of Physics and Technology.
Carbon atoms in graphene form a two-dimensional crystal with hexagonal cells.
The 2010 Nobel Laureate in Physics Andre Geim (born in 1958) is a professor at the University of Manchester (UK). Graduated from the Moscow Institute of Physics and Technology, defended his Ph.D. thesis at the Institute of Solid State Physics (Chernogolo
Nobel Laureate in Physics 2010 Konstantin Novoselov (born in 1974) is a professor at the University of Manchester (UK) and a graduate of the Moscow Institute of Physics and Technology. Worked at the Institute of Problems of Microelectronics Technology and
Graphene is one of the allotropic forms of carbon. It was first obtained by gradual exfoliation of thin layers of graphite. Graphene, folded, forms a nanotube or fullerene.
One of the possible applications of graphene is the creation on its basis of a new technology for deciphering the chemical structure (sequencing) of DNA. Scientists from the Kavli Institute of Nanoscience (Netherlands) led by Professor Dekke
Graphene, a material just one atom thick, is built from a "grid" of carbon atoms arranged like a honeycomb into hexagonal (hexagonal) cells. This is another allotropic form of carbon along with graphite, diamond, nanotubes and fullerene. The material has excellent electrical conductivity, good thermal conductivity, high strength and is almost completely transparent.
The idea of obtaining graphene "lay" in the crystal lattice of graphite, which is a layered structure formed by weakly bonded layers of carbon atoms. That is, graphite, in fact, can be represented as a set of graphene layers (two-dimensional crystals) interconnected.
Graphite is a layered material. It is this property that the Nobel laureates used to obtain graphene, despite the fact that the theory predicted (and previous experiments confirmed) that a two-dimensional carbon material cannot exist at room temperature - it will transform into other allotropic forms of carbon, for example, fold into nanotubes or into spherical fullerenes.
An international team of scientists led by Andre Geim, which included researchers from the University of Manchester (Great Britain) and the Institute for Problems of Microelectronics Technology and Highly Pure Materials (Russia, Chernogolovka), obtained graphene by simply exfoliating graphite layers. To do this, ordinary adhesive tape was glued onto the graphite crystal, and then removed: the thinnest films remained on the tape, among which were single-layer ones. (How can you not remember: “Everything ingenious is simple!”) Later, other two-dimensional materials were obtained using this technique, including the high-temperature superconductor Bi-Sr-Ca-Cu-O.
Now this method is called "micromechanical separation", it allows you to get the highest quality graphene samples up to 100 microns in size.
Another great idea of future Nobel laureates was the deposition of graphene on a substrate of silicon oxide (SiO 2 ). Thanks to this procedure, graphene became possible to observe under a microscope (from optical to atomic force) and to study.
The very first experiments with the new material showed that in the hands of scientists is not just another form of carbon, but a new class of materials with properties that cannot always be described from the standpoint of the classical theory of solid state physics.
The resulting two-dimensional material, being a semiconductor, has a conductivity similar to that of one of the best metal conductors - copper. Its electrons have a very high mobility, which is associated with the peculiarities of its crystal structure. Obviously, this quality of graphene, coupled with its nanometer thickness, makes it a candidate for a material that could replace in electronics, including future high-speed computers, silicon that does not meet current demands. Researchers believe that a new class of graphene nanoelectronics with a base transistor thickness of no more than 10 nm (a field-effect transistor has already been obtained on graphene) is not far off.
Now physicists are working on further increasing the mobility of electrons in graphene. Calculations show that the limitation of the mobility of charge carriers in it (and hence the conductivity) is associated with the presence of charged impurities in the SiO 2 substrate. If one learns how to obtain "free-hanging" graphene films, then the electron mobility can be increased by two orders of magnitude - up to 2×10 6 cm 2 /V. With. Such experiments are already underway, and quite successfully. True, an ideal two-dimensional film in a free state is unstable, but if it is deformed in space (that is, it is not perfectly flat, but, for example, wavy), then stability is ensured for it. Such a film can be used, for example, to make a nanoelectromechanical system - a highly sensitive gas sensor capable of responding even to a single molecule that appears on its surface.
Other possible applications of graphene: in the electrodes of supercapacitors, in solar cells, for the creation of various composite materials, including ultralight and high-strength ones (for aviation, spacecraft, etc.), with a given conductivity. The latter can be extremely different. For example, the graphane material was synthesized, which, unlike graphene, is an insulator (see "Science and Life" No.). It was obtained by attaching a hydrogen atom to each carbon atom of the starting material. It is important that all the properties of the starting material - graphene - can be restored by simple heating (annealing) of graphane. At the same time, graphene added to plastic (an insulator) turns it into a conductor.
The almost complete transparency of graphene suggests its use in touch screens, and if we recall its “superthinness”, then the prospects for its use for future flexible computers (which can be rolled up like a newspaper), watch bracelets, soft light panels are understandable.
But any application of the material requires its industrial production, for which the micromechanical separation method used in laboratory research is not suitable. Therefore, a huge number of other ways to obtain it are now being developed in the world. Chemical methods for obtaining graphene from graphite microcrystals have already been proposed. One of them, for example, produces graphene embedded in a polymer matrix. Vapor deposition, growth at high pressure and temperature, on silicon carbide substrates are also described. In the latter case, which is most suitable for industrial production, a film with the properties of graphene is formed by thermal decomposition of the surface layer of the substrate.
The value of the new material for the development of physical research is fantastically great. As Sergei Morozov (Institute for Problems of Microelectronics Technology and Highly Pure Materials of the Russian Academy of Sciences), Andre Geim and Konstantin Novoselov point out in their article published in 2008 in the journal Uspekhi fizicheskikh nauk, “in fact, graphene opens up a new scientific paradigm - “relativistic” physics of a solid state, in which quantum relativistic phenomena (some of which are not realizable even in high-energy physics) can now be studied under ordinary laboratory conditions ... For the first time in a solid-state experiment, all the nuances and diversity of quantum electrodynamics can be explored. That is, we are talking about the fact that many phenomena, the study of which required the construction of huge particle accelerators, can now be investigated armed with a much simpler tool - the thinnest material in the world.
Expert comment
We thought about a field effect transistor ...
The editors asked their colleague and co-author to comment on the results of the work of Nobel laureates Andre Geim and Konstantin Novoselov. Sergei Morozov, Head of the Laboratory of the Institute for Problems of Technology of Microelectronics and High-Purity Materials of the Russian Academy of Sciences (Chernogolovka), answers questions from Tatyana Zimina, a correspondent for Science and Life.
How did the idea to get a two-dimensional carbon material come about? In connection with what? Did you expect any unusual properties from this form of carbon?
Initially, we did not have a goal to get a two-dimensional material from a semi-metal, we tried to make a field-effect transistor. Metals, even one atom thick, are not suitable for this - they have too many free electrons. First, we got a countable number of atomic planes from a graphite crystal, then we began to make thinner and thinner plates until we got a single-atomic layer, that is, graphene.
Graphene has been considered by theorists for a long time, since the middle of the 20th century. They also introduced the very name of the two-dimensional carbon material. It was graphene that theorists (long before its experimental production) became the starting point for calculating the properties of other forms of carbon - graphite, nanotubes, fullerenes. It is also the most well described theoretically. Of course, theorists simply did not consider any effects now discovered experimentally. Electrons in graphene behave like relativistic particles. But no one had previously thought of studying what the Hall effect would look like in the case of relativistic particles. We discovered a new type of quantum Hall effect, which was one of the first striking confirmations of the uniqueness of the electronic subsystem in graphene. The same can be said about the Klein paradox inherent in graphene, known from high energy physics. In traditional semiconductors or metals, electrons can tunnel through potential barriers, but with a probability much less than one. In graphene, electrons (like relativistic particles) penetrate without reflection even through infinitely high potential barriers.
Why was it believed that a two-dimensional carbon material (graphene) would be unstable at room temperature? And then how did you get it?
The early work of theorists, which showed the instability of two-dimensional materials, referred to an infinite ideal two-dimensional system. Later work showed that in a two-dimensional system, long-range order can still exist (which is inherent in crystalline bodies. - Ed.) at a finite temperature (room temperature for a crystal is a fairly low temperature). The real graphene in suspension, however, is apparently not perfectly flat, it is slightly wavy - the height of the rises in it is of the order of a nanometer. In an electron microscope, these "waves" are not visible, but there are other confirmations of them.
Graphene is a semiconductor, if I understand correctly. But here and there I find the definition - semi-metal. What class of materials does it belong to?
Semiconductors have a band gap of a certain width. Graphene has zero. So it can be called a zero band gap semiconductor or a zero band overlap semimetal. That is, it occupies an intermediate position between semiconductors and semimetals.
In some places in the popular literature, other two-dimensional materials are mentioned. Has your group tried any of these?
Literally a year after obtaining graphene, we obtained two-dimensional materials from other layered crystals. These are, for example, boron nitride, some dichalcogenides, high-temperature superconductor Bi-Sr-Ca-Cu-O. They did not repeat the properties of graphene - some of them were generally dielectrics, others had very low conductivity. Many research groups in the world are engaged in the study of two-dimensional materials. Now we use boron nitride as a substrate for graphene structures. It turned out that this radically improves the properties of graphene. Also, if we talk about the use of graphene to create composite materials, boron nitride is one of its main competitors here.
- What are the most promising methods for producing graphene?
In my opinion, now there are two such main methods. The first is the growth on the surface of films of some rare earth metals, as well as copper and nickel. Then graphene must be transferred to other substrates, and this has already been learned to do. This technology is moving into the commercial development stage.
Another method is growing on silicon carbide. But it would be nice to learn how to grow graphene on silicon, on which all modern electronics is built. Then the development of graphene devices would have gone by leaps and bounds, since graphene electronics would naturally expand the functionality of traditional microelectronics.
