Karim Milanchian - Department of Physics, Payame Noor University, Tehran, Iran
Hakimeh Mohammadpour - Department of Physics, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, ۵۳۷۱۴-۱۶۱ Tabriz, Iran

Abstract: Discrete energy levels of quantum dots (QD) have electronic and optoelectronic applications. In this paper, a novel graphene nanoribbon (GNR) field effect transistor (FET) is modeled numerically using the NEGF formalism. In the new device model of this paper, the channel region is composed of one or two QDs, made by only one metallic gate electrode. This model utilizes a semiconductor armchair graphene nanoribbon through which the current may pass. The two highly doped ends of GNR act as source and drain contacts. At this unique model, one or two quantum dots form on GNR channel.  The discreteness of energy levels of the two coupled quantum dots, revealed by applying gate voltage, gives rise to resonant tunneling.  Resonant tunneling through these levels results in negative differential conductance. The coupling between QDs determines the current characteristics of device. Step-wise increment of current by increasing drain voltage manifests QDs discrete energy levels.

FET, Graphene, NEGF, Quantum Dot