24 September 2013 Current transport model of graphene nanoribbon tunnel transistor in variable and constant field
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In our earlier work1, we have developed an analytical current transport model of a p-channel Tunnel Field Effect Transistor (T-FET) made from 2D atomically thick Graphene Nanoribbon (GNR). Considering drain-source voltage (VDS), gate-source voltage (VGS), carrier mobility (μ) and top gate dielectric (tOX), the model demonstrates an ON current of 1605 μA/μm for a GNR width of 5nm at 0.275eV band gap. The calculated ON/OFF current ratio of 107 with a very steep Subthreshold-Slope (SS) of 7.07mV/decade is obtained from the I-VGS transfer characteristics. In the present work, current transport mechanism of graphene T-FETs considering constant and variable electric fields are proposed and corresponding I-V characteristics are obtained. The constant electric field model is based on tunneling mechanism of Esaki tunnel diode. The variable electric field model exhibits linear (Ohmic) I-V characteristics. Contrary to a variable electrical field, constant field model exhibits both linear and saturation regions of operation. Using back gated biasing, the n-channel TFET exhibits negative differential conductivity (NDC) for the variable electric field. The performance of GNR T-FET under constant electric field model is compared with the projected model of nMOSFETs in 2011 ITRS and found that the proposed model exhibits seven times lower power and eight times higher intrinsic speed in the upper GHz range. Such high performance makes graphene T-FET extremely suitable for design of ultra-low power RF integrated circuits.
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M. S. Fahad, M. S. Fahad, A. Srivastava, A. Srivastava, A. K. Sharma, A. K. Sharma, C. Mayberry, C. Mayberry, "Current transport model of graphene nanoribbon tunnel transistor in variable and constant field ", Proc. SPIE 8814, Carbon Nanotubes, Graphene, and Associated Devices VI, 88140L (24 September 2013); doi: 10.1117/12.2022909; https://doi.org/10.1117/12.2022909

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