Charge Transport in Polycrystalline Graphene: Challenges and Opportunities

TL;DR

This paper reviews the progress in understanding the structure, electrical, and chemical properties of polycrystalline graphene grain boundaries, highlighting their impact on device performance and potential for sensing applications.

Contribution

It provides a comprehensive overview of experimental and simulation studies on graphene grain boundaries, emphasizing their dual role as both a challenge and an opportunity.

Findings

Electrical and chemical properties of grain boundaries are strongly correlated.

Grain boundaries can be engineered for highly sensitive electrobiochemical devices.

Understanding grain boundaries can improve graphene device performance.

Abstract

Graphene has attracted significant interest both for exploring fundamental science and for a wide range of technological applications. Chemical vapor deposition (CVD) is currently the only working approach to grow graphene at wafer scale, which is required for industrial applications. Unfortunately, CVD graphene is intrinsically polycrystalline, with pristine graphene grains stitched together by disordered grain boundaries, which can be either a blessing or a curse. On the one hand, grain boundaries are expected to degrade the electrical and mechanical properties of polycrystalline graphene, rendering the material undesirable for many applications. On the other hand, they exhibit an increased chemical reactivity, suggesting their potential application to sensing or as templates for synthesis of one-dimensional materials. Therefore, it is important to gain a deeper understanding of the structure and properties of graphene grain boundaries. Here, we review experimental progress on identification and electrical and chemical characterization of graphene grain boundaries. We use numerical simulations and transport measurements to demonstrate that electrical properties and chemical modification of graphene grain boundaries are strongly correlated. This not only provides guidelines for the improvement of graphene devices, but also opens a new research area of engineering graphene grain boundaries for highly sensitive electrobiochemical devices.