Electronic Structures And Transport Properties Of Graphene Nanoribbons:A Recursive Green’s Function Study

Due to the novel physical properties, such as, abnormal quantum Hall effects, Klein tunneling and minimum conductivity, graphene nanoribbons have attract many scienctists’eyeballs. It is a strong candidate for the future photoelectric devices. Therefore, investigation on grapheme nanoribbons has high theoretic value and actual application signification. Because of the difficulty of preparing the perfect sample, the graphene layer with various defects becomes hot research topic around the world. In this thesis, based on the tight-binding method and the technique of recursive Green’s function, we study the electronic structures and transport properties of graphene nanoribbons with edge and body defects. The results are displayed as follows:1.The conductance of the metallic graphene nanoribbons will be greatly modified at the cases of the existence of edge defects. With the concentration of edge defects increases, the conductance suppression is more significant and a conductance gap will be developed which can be explained by the localization of electronic states.2.The electronic structures and transport properties of graphene nanoribbons are investigated. The results show that conductance curves are sensitively dependent on the body vacancies. The quantum conductance steps are smoothed out when a body vacancy appears in the system. Interestingly, we find that there exist resonant transmission peaks on the conductance curves at the low energy when two body vacancies appear in the system. Especially, the distance between two vacancies determines the number of resonant transmission peaks. One more resonant transmission peak will appear as the distance increases for three supercells. These results will provide guidance on experimental design.