|Michael Sullivan Online|
Electron transmission modes in electrically biased graphene nanoribbons and their effects on device performance
Lei Shen, Minggang Zeng, Suchun Li, Michael B. Sullivan, and Yuan Ping Feng
Department of Physics, 2 Science Drive 3, National University of Singapore, Singapore 117542, Singapore
Institute of High Performance Computing, 1 Fusionopolis Way, Connexis 138632, Singapore
Received 4 November 2011; revised 26 July 2012; published 14 September 2012
Phys. Rev. B 2012, 86, 115419.
Using ab initio transport methods, we investigate electron transmission modes (channels, pathways, and intensities) in electrically biased graphene nanoribbons (GNRs) under different growth conditions. In addition to the bond currents, we report loop currents in such devices, induced by the electrons hopping between carbon atoms of the same sublattice under bias. The loop current channel as well as the bond current channel play an important role in the local current in electrically biased GNR-based devices. The effect of edge functional groups and surface defects/groups on device performance depends on the current pathway and intensity in these two channels. Understanding the details of local currents in GNRs paves the way to make high-performance GNR-based electronic devices, such as GNR field effect transistors.