Multi-scale Incoherent Electronic Transport Properties in Non-ideal CVD Graphene Devices

TL;DR

This study models electronic transport in non-ideal CVD graphene devices using multi-scale quantum transport formalism to understand mobility degradation caused by various scattering mechanisms in real-world applications.

Contribution

It introduces a comprehensive multi-physics, multi-scale quantum transport model that incorporates multiple scattering sources to analyze mobility degradation in CVD graphene devices.

Findings

Scattering mechanisms significantly impact device mobility.

Transmission and current-voltage characteristics vary with scattering potentials.

The model quantifies the effect of contact and phonon scattering on transport.

Abstract

In this research work, roll-to-roll chemical vapor deposited graphene device electronic transport properties are benchmarked to elucidate and comprehend mobility degradation in the real-world commercial application of graphene devices. Multifarious device design morphology in the graphene and two-dimensional material with diverse background materials compositions and processing recipes incorporate various scattering sources in the devices. To understand the nature of mobility degradation in roll-to-roll chemical vapor deposited graphene production devices, we employed multi-scale, multi-physics bottom-up, non-equilibrium Green's function-based quantum transport formalism. In this framework, we numerically incorporate various scattering mechanisms to deduce the measurand mobility at the last stage of computation to observe various scattering potential impacts on the production device performance. We have analyzed the variation in transmission, electronic charge density, electrostatic Poisson potential, energy-resolved flux density, and current-voltage characteristics and inferred the Drude mobility with different scattering potentials in various graphene devices. These scattering mechanisms treat scattering potentials as the first-order phonon Dyson self-energy term in the third loop of the two-looped self-consistent Poisson-Non-equilibrium Green's function iteration. Furthermore, multiple scattering scenarios implemented through a generalized contact self-energy scattering calculation ascribe the effect of contact scattering to the graphene device in quasi-ballistic transport limit. In this scheme, the effect of all the physical scattering mechanisms is lumped into one energy uncertainty or scattering rate parameter to include in the device's contact self-energy interaction term bound by the upper limit of Heisenberg uncertainty for the interacting quantum charged particles.