RT - Journal Article T1 - The Effect of Graphene Nano-ribbon Chirality on the Transmission Coefficient and Energy Gap JF - jsci YR - 2013 JO - jsci VO - 12 IS - 4 UR - http://jsci.khu.ac.ir/article-1-1501-en.html SP - 669 EP - 676 K1 - Nano-ribbon K1 - Electronic Conductance K1 - Energy gap K1 - Green’s function K1 - tight-binding AB - In this paper, we studied the electronic conductance and energy gap of a graphene nano-ribbon which is connected to two semi-infinite atomic chains by the atoms located in the opposite sides of nano-ribbon. The numerical calculations were performed using the Green’s function method in the nearest neighbor approximation of tight-binding approach. The conductance curves plotted with respect to incoming electron energy show that for a zigzag graphene nano-ribbon with one benzene ring in its width, there is no gap in the energy band spectra of the system, while for the armchair case, an energy gap always exists around the Fermi energy and its value depends on the size of the nano-ribbon. The results show that the behavior of the graphene nano-ribbons conductance strongly depends on that how and where the leads connect to the nano-ribbon and on the contacts qualities. LA eng UL http://jsci.khu.ac.ir/article-1-1501-en.html M3 ER -