Russian physicists have found why nanotubes are good conductors

© Photo : Joel Brehm, University of Nebraska-Lincoln Office of Research and Economic DevelopmentТрехмерная visualization of carbon nanotubes of variable diameterRussian physicists have found why nanotubes are good conductors© Photo : Joel Brehm, University of Nebraska-Lincoln Office of Research and Economic Development

Physics from MIPT and the RAS institutes found an explanation for why carbon nanotubes conduct electricity as well as do the metals, according to a paper published in the journal Carbon.

«Our results show that these films of carbon nanotubes can be used as components and assemblies in the various fields of micro — and optoelectronics», — said Elena Zhukova, one of the authors of the opening of the Moscow Institute of physics and technology in Dolgoprudnyy, whose word brings the press service of the University.

Since the discovery of carbon nanotubes in 1991, they predicted a future in modern industry. They have many useful properties — good electrical and thermal conductivity, high strength and mechanical resistance. First experiments have shown that nanotubes are extremely difficult to apply in practice due to their small size and difficulties in their connection and interweaving into a single fiber.

On the other hand, the addition of nanotubes in other materials, or their «insert» in the cells of living creatures were more promising thing. For example, recently scientists have found that embedding the nanotubes into the leaves of plants makes them ultra-sensitive detectors of explosives, glowing with the appearance in the air of traces of their molecules and triples the efficiency of photosynthesis.

Russian scientists unexpectedly found out why nanotubes conduct electricity as well as do the metals, by studying how similar carbon structures interact with light and electric fields.

To do this, physicists have produced a small amount of single nanotubes and combined them into the film, similar to those used in the manufacture of flexible displays and touch panels. Then enlighten them with infrared rays and terahertz radiation by observing how varied their range while passing through the pure carbon nanostructures, and a tube containing a small amount of impurities in the form of atoms and ions of copper and chlorine.

Studying the behavior of nanotubes under near-zero and room temperatures, scientists unexpectedly discovered that the «pure» versions of these nanostructures interact with light and electric fields are actually the same, as do the metals, placed in similar conditions. This is radically contrary to what previously obtained by other groups of physicists during the previous experiments. According to Russian scientists, this is due to the fact that their colleagues used nanotubes with a large number of impurities that hinder the disclosure of actual electrical properties of these nanostructures.

The new data, according to the authors, suggests that this form of carbon conducts current according to the same principles as conventional metals inside them there are many free electrons can move through the nanotube and participate in the transmission of oscillations of the electromagnetic field.

This not only explains why nanotubes are good conductors, but allows the flexibility to control their properties using the same laws that are used today to describe the physical properties of metals. It is, as scientists believe, will help accelerate the penetration of nanotubes in electronic industry and other spheres of human life.