Bandgap nanoengineering of graphene tunnel diodes and tunnel transistors to control the negative differential resistance
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Bandgap nanoengineering of graphene tunnel diodes and tunnel transistors to control the negative differential resistance Viet Hung Nguyen · Jérôme Saint-Martin · Damien Querlioz · Fulvio Mazzamuto · Arnaud Bournel · Yann-Michel Niquet · Philippe Dollfus
Published online: 31 January 2013 © Springer Science+Business Media New York 2013
Abstract By means of numerical simulation based on the Green’s function formalism on a tight binding Hamiltonian, we investigate different possibilities of achieving a strong effect of negative differential resistance in graphene tunnel diodes, the operation of which is controlled by the interband tunneling between both sides of the PN junction. We emphasize on different approaches of bandgap nanoengineering, in the form of nanoribbons (GNRs) or nanomeshes (GNMs), which can improve the device behaviour. In particular, by inserting a small or even zero bandgap section in the transition region separating the doped sides of the junction, the peak current and the peak-to-valley ratio (PVR) are shown to be strongly enhanced and weakly sensitive to the length fluctuations of the transition region, which is an important point regarding applications. The study is extended to the tunneling FET which offers the additional possibility of modulating the interband tunneling and the PVR. The overall work suggests the high potential of GNM lattices for designing high performance devices for either analog or digital applications.
V. Hung Nguyen · J. Saint-Martin · D. Querlioz · F. Mazzamuto · A. Bournel · P. Dollfus () Institute of Fundamental Electronics (IEF), CNRS, UMR 8622, Univ. Paris-Sud, Orsay, France e-mail: [email protected] V. Hung Nguyen Center for Computational Physics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi, Vietnam V. Hung Nguyen · Y.-M. Niquet L_Sim, SP2M, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble, France
Keywords Graphene device · Dirac fermions · Green’s function · Quantum transport · Negative differential resistance · Tunnel diode · Tunnel transistor
1 Introduction The effect of negative differential resistance (NDR) has been widely investigated in devices based on conventional semiconductors, e.g. the Esaki tunnel diode or the double-barrier resonant tunnelling diode. This effect is suitable for a wide range of high-frequency applications [1]. Given the peculiar tunnelling properties of chiral particles in graphene [2] and the potential of this material for high speed electronics [3], it sounds appealing to investigate the possibility to generate and control an NDR in graphene devices. Actually, different suggestions of graphene structures and devices exhibiting an NDR behaviour have been proposed, based on various physical mechanisms. It has been predicted that the parity selective rule [4] existing in perfect zigzag (Z) GNRs with an even number of zigzag lines may generate a negative differential resistance [5]. The mismatch of modes in the left and right sides of a P+ P ZGNR junction may also induce an NDR regardless of the width of the
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