Zhuckov V., Osadcha O. V.

Oles Honchar Dnipropetrovsk National University

 THE ASPECTS OF RESEARCHING PHYSICAL PROPERTIES OF GRAPHENE

The problem of looking for new semi-conductor materials for using in electronics is vital nowadays. It can be explained, first of all, by the fact that there is serious shortage of silicon which is the most accessible and widely used semi-conductor. Trying to find a solution to this problem, scientists turned to a newly-discovered super-material – graphene. Graphene is the first material that is two-dimensional. This gives it unique properties. 2D materials display very interesting properties, and are fundamentally different from the 3D materials we encounter everyday. The discovery of 2D materials means that scientists now have access to materials of all dimensionalities, including 0D (quantum dots, atoms) and 1D (nanowires, carbon nanotubes)

Since 1959 many scientists have been looking for graphene using complex experiments. But the first crystals of graphene were discovered in 2004 using a very simple and effective method – namely ordinary scotch tape! During experiments in Manchester, scientists noticed small parts of graphene on the tape used to clean a graphite stone. These two scientists Andre Gain and Konstantin Novoselov in 2010 were awarded Nobel Prize in Physics for this simple but groundbreaking experiment.

Thanks to the scotch tape method this area of the science grew extremely quickly. And today hundreds laboratories all over the world deal with different aspects of graphene-researches.

Graphene has a combination of unique properties. First of all, graphene is the first 2-D crystal ever known to us and the thinnest object ever obtained and also the lightest one. Furthermore, graphene is the world strongest material harder than diamond and about 300 times stronger than steal. Graphene conducts electricity muck better than copper. It is transparent material. Also graphene is bendable and can take any form you want. And this unique super-material gave birth to a new class of crystals that are also just one atom thin! And what is more fantastic is that this can be shuffled with each other to engineer new materials on demand to meet the special needs of different industries.

There are theories which show that graphene should not be able to exist without being destroyed by thermal fluctuations. These fluctuations should cause the crystal to melt. Workers who tried to create atomically thin films of other materials in the past found that the films were unstable and tended to separate and 'clump up' rather than form perfect layers. In fact, anyone who has ever written with a pencil has probably created graphene flakes.

Graphene can be used for many different purposes including:

- transistors: Graphene can be used to make excellent transistors. It is so thin we can easily control whether or not it conducts by applying an electric field. We would like to be able to do this with metals, but we cannot make metal films thin enough to affect their conducting state in this way. Electrons in graphene also travel ballistically over sub-micron distances. As a result, graphene-based transistors can run at higher frequencies and more efficiently than the silicon transistors we use now. At the present moment we have no way to produce entire integrated circuits from these transistors since we are limited by the size of graphenes that can be produced.

 – gas sensors: Gas molecules that land on graphene affect its electronic properties in a measurable way. In fact, scientists have measured the effect of a single molecule associating with a graphene. This means that we can create gas sensors which are sensitive to a single atom or molecule!

- inert coatings: Graphene is resistant to attack by many powerful acids and alkalis such as hydrofluoric acid and, so one day could be used to give objects an atomically thin protective coating which would provide protection against these agents.

All these factors move graphene from the laboratories to the market place driven by demand from industries where such super materials are required: automotive, electronics, energy storage, communication, sensors, soars, oil and etc. The discovery of graphene has provided opportunity for scientists to investigate these possibilities. Thanks to mass production methods that have been intensively developed graphene is likely to appear in the surrounding world soon.