Program

P.65 -- Poster, NCTP-41

Date: Wednesday, 3 August 2016

Time: 08h30 - 10h00

Controllable electronics structure in Zigzag Bilayer Graphene nanoribbons

Vu Thanh Tra (1), Nguyen Thi Kim Quyen (2), Tran Van Truong (3)

(1) Department of Physics, School of Education, Can Tho University, Can Tho, Vietnam. (2) School of Graduate, College of Natural Sciences, Can Tho University, Can Tho, Vietnam. (3) IEF, Université Paris-sud, CNRS, UMR 8622, Bât 220, 91405 Orsay, France.

Graphene, consisting of one or a few crystalline monolayers of carbon atoms, stands out because of its electronic properties for applications in nanoelectronics. However, this material also suffers from a strong drawback for most electronic devices due to the gapless character of its band structure, which makes it difficult to switch off the current. In our model, we propose a method to control the gap. We use a transverse electric field generated by side gates and a vertical electric field generated by top/back gates to modulate the band gap and investigate the electronic structure of Zigzag Bilayer Graphene nanoribbons (Bernal stacking) based on the Tight Binding calculation method. The band structure of Zigzag Bilayer Graphene has flat bands, which appear in the range of 2pi/3 - pi . Under the effects of an external electric field, the gap is opened depending on its value. Specifically, in this case, the gap will be changed most when U is in the range of [0.5V, 1.5V]. Comparing the electric fields perpendicular to parallel the difference was found to be larger in the parallel field, but the arranging order of the charged particles was changed to a greater amount in the shape of band structure of Zigzag Bilayer Graphene nanoribbons. More importantly, the value of the bandgap is largest under simultaneous effects of the two fields. Then, our group continued to examine the effects on transmission and Seebeck coefficients to control their physical properties under electric fields. So, thanks to the application of external electric fields, we can open and control the gap of Zigzag Bilayer Graphene nanoribbons . We believe that our results highlight a promising direction for Graphene-based semiconductors that can be used to create new electronic devices with a high on/off current ratio. This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 103.01-2015.98

Presenter: Nguyen Thi Kim Quyen