Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (03): 559-563.doi: 10.3866/PKU.WHXB20110305


Electronic Transport in Z-Shaped Graphene-Nanoribbons: Shape and Size Effects

XU Ning1, KONG Fan-Jie1, WANG Yan-Zong2   

  1. 1. Department of Physics, Yancheng Institute of Technology, Yancheng 224051, Jiangsu Province, P. R. China;
    2. Department of Physics, Huaiyin Institute of Technology, Huaiyin 223003, Jiangsu Province, P. R. China
  • Received:2010-10-12 Revised:2010-12-27 Published:2011-03-03
  • Contact: XU Ning
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10874052) and Foundation for the Author of National Excellent Doctoral Dissertation of China (200726).


Based on the Green′s function method and the Landauer-Büttiker formula, we studied the electronic transport properties of a graphene heterojunction. This was a Z-shaped graphene nanoribbon (GNR), which was connected by zigzag graphene nanoribbon leads. We show that the conductance of the Z-shaped GNRs is highly sensitive to the shape and size of the heterojunctions. The charge density is strongly localized on the zigzag edge sites of the leads and thereby a conductance dip or gap results at the Fermi energy. By varying the width of the graphene ribbons between the junctions, we found many more resonant peaks in the conduction because of the quasi-bound states. The number of resonant peaks has little to do with the length of the graphene ribbons between the junctions. Importantly, we show that in the low-energy region the electrons retain their ballistic transport characteristic in the width uniformity of Z-shaped GNRs with included angle θ of 60° or 150° turns. These findings show that the Z-shaped GNRs can be selected for future ballistic device applications.

Key words: Tight-binding model, Green′s function, Graphene-nanoribbon, Conductance