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Glukhova O.E.^1,2, Slepchenkov M.M. ¹

1 – Saratov State University, Saratov, Russia

2 – I.M. Sechenov First Moscow State Medical University, Moscow, Russia

glukhovaoe@info.sgu.ru

In this paper, we suggest an idea of a new approach to control the electrical conductivity and its anisotropy in graphene-nanotube films with vertically oriented single-walled carbon nanotubes (SWCNTs) seamlessly connected to graphene. The basis of this approach is the phenomenon of aromaticity occurred in the hexagons of armchair-type SWCNTs at a certain nanotube length, which induces the oscillations of electronic characteristics with increasing the SWCNT length [1]. The proposed idea was tested on the example of two graphene nanomesh (GNM) atomistic models with nanoholes for SWCNTs with the chirality (6,6) and (9,9) in the case of sequentially increasing the SWCNT length. These types of SWCNTs were revealed using original approach called “virtual growing”, which shown that among the armchair SWCNTs with a diameter of 0.6–1.2 nm, the energetically favorable SWCNT- graphene junction will be formed with the SWCNTs (6,6) and (9,9). The calculations of geometric parameters of graphene-nanotube atomistic models were obtained using the self-consistent charge density functional tight-binding (SCC-DFTB) method [2]. The calculations of the electron transmission function T(E) and electrical conductivity G were carried out at 300 K using the Landauer-Buttiker formalism [3]. It was found that the nanoholes in monolayer graphene form conducting pathways in one direction, inducing anisotropy of the conducting properties. The anisotropy of the G value reaches 5 times. The formation of SWCNTs in the nanoholes does not remove anisotropy, amplifying it up to 7 times. The value of electrical conductivity G is strongly influenced by the length of the formed nanotube. It was found that a sharp increase in the value of G occurs at a certain length of 0.615 nm, 0.984 nm, 1.353 nm, and so on with in steps of 0.369 nm. These values of the SWCNT length were determined by the number of atomic layers in the SWCNT framework that is a multiple of three. Especially noticeable jumps in electrical conductivity occur for the armchair direction of electron transport. Thus, by adjusting the SWCNT length, it is possible to enhance or weaken the anisotropy of the conductive properties of graphene-nanotube films.

Acknowledgement. This work was supported by the Ministry of Science and Higher Education of the Russian Federation, grant FSRR-2020-0004.

References:

[1] F. Buonocore, F. Trani, D. Ninno, A. Di Matteo, G. Cantele, G. Iadonisi, Nanotechnology, 19, 025711 (2008).

[2] M. Elstner, D. Porezag, G. Jungnickel, J. Elsner, M. Haugk, Th. Frauenheim, S. Suhai, G. Seifert, Phys. Rev. B 58, 7260 (1998).

[3] S. Datta, Quantum Transport: Atom to Transistor. 2nd ed. Cambridge: Cambridge University Press; 2005

O.E. Glukhova received Ph.D. in Vacuum and Plasma Electronics (1997) and Dr. Sc. in Solid State Electronics and Nanoelectronics (2009) from the Saratov State University, Russia. She is a head of Department of Radiotechnique and electrodynamics at Saratov State University and leads the Division of Mathematical modeling in Educational and scientific institution of nanostructures and biosystems at Saratov State University. Her main fields of investigation are: nanoelectronics, molecular modeling of biomaterials and nanostructures, molecular electronics, mechanics of nanostructures, quantum chemistry and molecular dynamics, carbon nanostructures (fullerenes, nanotubes, graphene, graphane). She has published more 200 peer-reviewed journal papers and five monographs.