Abstract Template

Pankaj Sharma, Laurent Syavoch Bernard, Antonios Bazigos, Arnaud Magrez and Adrian M. Ionescu École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland [email protected] Abstract Negative differential resistance (NDR) is a phenomenon in which an increase in voltage across the device's terminals results in a decrease in electric current through it. This is in contrast to a resistor in which an increase of applied voltage causes an increase in current due to Ohm's law. This unique phenomena can be exploited in numerous interesting applications, including high frequency oscillators, amplifiers, logic, memories and analog-to-digital converters. The NDR behavior can be realized with graphene transistors at high fields, thanks to its field-dependent carrier density and carrier-dependent saturation velocity, and has been demonstrated experimentally by few groups. [1]–[3] In this work, we report the observation of NDR in the output characteristics of graphene transistors fabricated using monolayer graphene grown by large-scale chemical vapor deposition process. The NDR here was demonstrated for various channel lengths ranging from 200 nm to 5 μm by employing wide channels, small un-gated regions, dual gating and thin top-gate dielectric. [4] Figure 1 shows the schematic view of the fabricated graphene transistor. Figure 2 shows the transfer characteristics of graphene transistor for 500 nm long and 30 μm wide channel having an equivalent oxide thickness of 2.5 nm. [4] Figure 3 shows the output characteristics for the same device. At the bias VBG = − 40 V, we see the decrease in the drain current (ISD) as drain voltage (VSD) is increased beyond VSD> 1.5 V, resulting in NDR. This effect is also reflected in the corresponding differential conductance (gDS = dISD dVSD ) showing negative values between VSD = 1.5 V and VSD = 1.98 V.