一种新型结构的石墨烯纳米器件的分析.docx

南京邮电大学硕士研究生学位论文 ABSTRACT
ABSTRACT
Graphene, as an ideal realization of two-dimensional crystals, has a promising future due to its unique electronic and physical properties. Owing to the excellent electrical properties and the characteristics that graphene ribbo ns can be cut easily with a designed shape and size, graphene is considered as candidates to make next generation electronic devices.
Green’s function expression has been calculated using Green’s function and Landa uer-Büttiker formulation in tight-binding approximation. Band structure of graphene has been calculated using Poisson equation and quantum transport equation. prehensive studies on the electronic transpo rt of the ladder-shaped graphene structure and bilayer graphene structure can provide physical insight and guidance for further optimization and theoretical studies of new graphene devices.
First, we have de monstrated the band structure and electronic transport prope rties of
two-dimens ional and one-dimens ional grapheme, and we have calculated the transmission probability through a po tential step or a po tential barrier in the graphene nonor ibbon.
Second, the simulated results show that conductance pe ak o f the graphene structures split in
as the symmetrical center and decrease until they disappear, with increasing of the ladders. The peaks of conductance will be suppressed with increasing of ladder interval.
Finally, we have demonstrated the electronic transport properties of several bilayer graphe ne structures, which are different shapes and different number of graphene surfaces. The results show that: the singl e layer structure conductance forms the envelope which is similar to double structure conductance, but the conductivity of discrete features disappear. Conductance peak of the bilayer graphene structure occur split, and conductance peak of the bilayer graphene structure decrease around , with increasing of the uppe r graphene number.
Keywords: Graphene; Tight-b