Intrinsic Limits of Subthreshold Slope in Biased Bilayer Graphene Transistor

TL;DR

This paper analyzes the fundamental limitations of the subthreshold slope in biased bilayer graphene transistors, revealing intrinsic electronic and electrostatic factors that prevent reaching the ideal Boltzmann limit, and highlighting potential for technological improvements.

Contribution

It introduces a coupled self-consistent Poisson-bandstructure solver to study the intrinsic bias dependence of bilayer graphene transistors, providing insights into their subthreshold slope limitations.

Findings

Subthreshold slope is limited above the Boltzmann limit due to intrinsic electronic structure.

The intrinsic bias dependence causes the subthreshold slope to be well above 60mV/decade.

Experimental results are below the theoretical intrinsic limit, indicating room for technological enhancement.

Abstract

In this work, we investigate the intrinsic limits of subthreshold slope in a dual gated bilayer graphene transistor using a coupled self-consistent Poisson-bandstructure solver. We benchmark the solver by matching the bias dependent bandgap results obtained from the solver against published experimental data. We show that the intrinsic bias dependence of the electronic structure and the self-consistent electrostatics limit the subthreshold slope obtained in such a transistor well above the Boltzmann limit of 60mV/decade at room temperature, but much below the results experimentally shown till date, indicating room for technological improvement of bilayer graphene.