Contact-Induced Negative Differential Resistance in Short-Channel Graphene FETs

Author

Grassi, Roberto ; Low, Tony ; Gnudi, Antonio ; Baccarani, Giorgio

Author_Institution

E. De Castro Adv. Res. Center on Electron. Syst. (ARCES), Univ. of Bologna, Bologna, Italy

Volume

60

Issue

1

fYear

2013

fDate

Jan. 2013

Firstpage

140

Lastpage

146

Abstract

In this paper, we clarify the physical mechanism for the phenomenon of negative output differential resistance (NDR) in short-channel graphene FETs through nonequilibrium Green´s function simulations and a simpler semianalytical ballistic model that captures the essential physics. This NDR phenomenon is due to a transport mode bottleneck effect induced by the graphene Dirac point in the different device regions, including the contacts. NDR is found to occur only when the gate biasing produces an n-p-n or p-n-p polarity configuration along the channel, for both positive and negative drain-source voltage sweep. In addition, we also explore the impact on the NDR effect of contact-induced energy broadening in the source and drain regions and a finite contact resistance.

Keywords

Green´s function methods; contact resistance; electromagnetic wave polarisation; field effect transistors; graphene; negative resistance; NDR effect; NDR phenomenon; contact-induced energy broadening; contact-induced negative differential resistance; device region; drain region; finite contact resistance; gate biasing; graphene Dirac point; n-p-n polarity configuration; negative drain-source voltage sweep; negative output differential resistance; nonequilibrium Green function simulation; p-n-p polarity configuration; positive drain-source voltage sweep; semianalytical ballistic model; short-channel graphene FET; source region; transport mode bottleneck effect; Electrostatics; Junctions; Logic gates; Mathematical model; Numerical models; Resistance; Graphene FETs; negative differential resistance; nonequilibrium Green´s function;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2012.2228868

Filename

6375800