Carbon is the most important element of most organic materials in the world. The carbon atoms are linked with each other to form materials like diamond or coal. Among the huge range of carbon made products, grapheme is one which is widely used by scientists. It can be counted as a nanotube which is a single atom that is thick and as a flat sheet. It is also an excellent conductor. The conductor is a substance that can carry electrons, i.e. electricity. Working with graphene is difficult as they cannot easily be separated and the basic form and comes in large sizes.
Creating a narrow graphene
An article in Science describes the use of atomic force microscope or the AFM for creating graphene as narrow as 12 nanometers. It can be produced on an insulting (elements that do not carry electron) surface, made from graphene oxide. In this procedure, the reaction is because of the temperature and the authors of the article were successful to adjust the resistivity by changing the heat that is produced from the tip of the AFM.
Graphene oxide is formed from chemical reactions of graphene sheet. Depending on the process, there are different degrees of oxidation. For every case, the structure of the sheet is dislocated and that makes it thicker. This provides more resistivity for both electrical conductivity and friction. This parameter varies with the oxidation state of graphene.
The advantages of the reversibility of graphene oxide
The most important fact that makes the graphene oxide special is the reversibility of the oxidation. By applying heat, the graphene can be separated from graphene oxide; which is known as a reduction chemical reaction. The result of the reaction gives us the required graphene with lower friction and higher conductivity.
The whole research is based on the location control and using the AFM for extending the heat. Converting the heat level to over 600°C of the AFM tip as well as running it over the graphene oxide surface can produce a 12nm thick sheet. No other common techniques like the conductive AFM (CAFM), ultrahigh-vacuum (UHV), Raman spectroscopy, friction force microscopy (FFM) and Kelvin probe force microscopy (KPFM) were used in the experiment.
So far, the results show that the channels act like a wire with low resistance and low friction. The difference in the resistivity levels of the wires and nearby objects are about four orders of magnitude.
Importance of temperature control
The reduction reaction is sensitive to temperature. So, having control over the heat is very important if you want to be successful in the experiment. The researchers should control the temperature between 150°C to 700°C of the AFM tip. The consequential materials later act distinctly if tested for electric resistance and friction. This makes it possible to use individual element as a single device.
There is also a chance of rewiring while using the graphene oxide. Another important result may be that as the reaction is sensitive to temperature, it might be possible to pass lower electricity through semiconducting channel without making any changes and for the permanent resistance reducing, a higher level of electricity may be necessary.