Variable Range Hopping in Carbon Nanotubes

Zishan      H. Khan; Samina      Husain; M.      Husain

Abstract

Carbon nanotubes exhibit exceptional properties that are a consequence of their symmetric structure. Many properties of carbon nanotubes (CNTs) have been explained in the wider context of materials science, thereby highlighting the contribution from different researchers worldwide in this rapidly expanding field. Among various other properties of CNTs studied so far, the electrical transport properties are still unclear and needs a lot of attention. Due to high anisotropy of graphite, the electrical properties are strongly dependent on the structure of the nanotubes. Since, the CNTs can be metallic and semi-conducting in nature, their explanation to electrical conduction mechanism in these two cases would be different. During the last few years, efforts have been made to understand the electrical transport phenomenon in CNTs, aiming at the design of nanoelectronic devices made solely of carbon. Keeping in view the above, it is of great interest to present a state of art on the progress involving the research work on electrical conduction mechanism especially variable range hopping in CNTs. In the present paper, we have presented a review on electrical transport mechanism especially variable range hopping in carbon nanotubes. This review will provide a better understanding of variable range hopping in CNTs.

Keywords: Carbon nanotubes, multi-walled carbon nanotubes, single-walled carbon nanotubes, individual carbon nanotube, e-beam lithography, focused ion beam, electrical transport properties, variable range hopping, MWNTs, covalent bonds, hexagons, Ohm's law, conductor, electrical transport, WL, MR, UCF, A-B, DOS, Bloch's theorem, Coulomb interaction energy, M-VRH, ES-VRH, resistivity, temperature, D-band, G-band, EPR, B-doping, LPCVD, SEM, TEM, HRTEM, FESEM, GNRs, SG-CNTs, 1D localization length, FIBB, TLT, CGVRH