Program

O.2 -- Oral, NCTP-40

Date: Monday, 27 July 2015

Time: 11h20 - 11h40

Transport gap in strained graphene heterochannels

M. Chung Nguyen (1,2), V. Hung Nguyen (1,2), H. Viet Nguyen (1) and P. Dollfus (2)

(1) Center for Computational Physics, Institute of Physics, VAST, Hanoi, Vietnam; (2) Institut d’Electronique Fondamentale, Université Paris Sud, Orsay, France

Due to its unusual electronic structure and excellent physical properties, graphene has become an attractive material in several research fields [1]. However, applications of graphene in electronic devices are still questionable due to its gapless character. Hence, many nanostructuring techniques (e.g., graphene nanoribbons [2], graphene bilayer with a perpendicular electric field [3], graphene nanomesh lattices [4], channels based on vertical stack of graphene layers [5], graphene/hexagonal boron nitride [6], nitrogen-doped graphene [7], and so on), to open a bandgap in this material have been suggested. However, each method still has its difficulties in the fabrication and need to be further confirmed by experiments. Recently, strain has been shown to be an alternative/promising approach to modulating the electronic properties of this material. In current works [8,9], we found that though it can not change the gapless character of 2D graphene channel, a small strain (i.e., ~ a few percent) can lead to a significant deformation of graphene's bandstructure. In graphene strain junctions, this results in a misalignment of Dirac cones of different graphene sections in the k-space and hence a large energy-gap (i.e., a few hundred meV) of transmission can be achieved. Moreover, it has been shown that the effect is strongly dependent not only on the strain magnitude but also on the strain direction and lattice orientation. On this basis, such strain heterochannels have been demonstrated to be very promising for enlarging the applications of graphene devices as in transistors or strain and thermal sensors. References; [1] A. C. Ferrari et al., Nanoscale 7, 4598 (2015); [2] M. Y. Han et al., Phys. Rev. Lett. 98, 206805 (2007); [3] Y. Zhang et al., Nature 459, 820 (2009); [4] J. Bai et al., Nat. Nanotechnol. 5, 190 (2010); [5] L. Britnell et al., Science 335, 947 (2012); [6] N. Kharche et al., Nano Lett. 11, 5274 (2011); [7] A. Zabet-Khosousi et al., J. Am. Chem. Soc. 136, 1391 (2014 ); [8] V. H. Nguyen et al., Nanotechnology. 25, 165201 (2014); [9] M.C. Nguyen et al., Semicond. Sci. Technol. 29 115024 (2014); Physica E (2015) in press (http://arxiv.org/abs/1505.06474)

Presenter: Nguyen Mai Chung