Electrical Resistivity of Polycrystalline Graphene: Effect of Grain-Boundary-Induced Strain Fields

TL;DR

This study models how grain-boundary-induced strain fields significantly influence electron scattering and electrical resistivity in polycrystalline graphene, revealing the dominant role of deformation potential scattering under typical conditions.

Contribution

The paper introduces a comprehensive model incorporating microscopic grain boundary structure and strain effects, advancing understanding of resistivity mechanisms in polycrystalline graphene.

Findings

Resistivity ranges from 0.1 to 10 kΩ·μm depending on grain boundary type.

Resistivity increases with decreasing grain boundary size, exceeding 60 kΩ·μm.

Irregularities at grain boundaries can increase resistance by over an order of magnitude.

Abstract

We have revealed the decisive role of grain-boundary-induced strain fields in electron scattering in polycrystalline graphene. To this end, we have formulated the model based on Boltzmann transport theory which properly takes into account the microscopic structure of grain boundaries (GB) as a repeated sequence of heptagon-pentagon pairs. The effect of strain field is described within the deformation potential theory. For comparison, we consider the scattering due to electrostatic potential of charged grain boundary. We show that at naturally low GB charges the deformation potential scattering dominates and leads to physically reasonable and, what is important, experimentally observable values of the electrical resistivity. It ranges from 0.1 to 10 k$\Omega $$\mu $m for different types of GBs with a size of 1 $\mu$m and has a strong dependence on misorientation angle. For low-angle highly charged GBs, two scattering mechanisms may compete. The resistivity increases markedly with decreasing GB size and reaches values of 60 k$\Omega $$\mu $m and more. It is also very sensitive to the presence of irregularities modeled by embedding of partial disclination dipoles. With significant distortion, we found an increase in resistance by more than an order of magnitude, which is directly related to the destruction of diffraction on the GB. Our findings may be of interest both in the interpretation of experimental data and in the design of electronic devices based on poly- and nanocrystalline graphene.