Electrochemistry at the Edge of a Single Graphene Layer in a Nanopore

Shouvik Banerjee †‡, Jiwook Shim ‡§, Jose Rivera ‡,Xiaozhong Jin ¶#, David Estrada ‡§, Vita Solovyeva‡§, Xueqiu You , James Pak , Eric Pop ‡§#,Narayana Aluru ¶#, and Rashid Bashir ‡§*

^†Department of Materials Science and Engineering,^‡Micro and Nanotechnology Laboratory, ^§Department of Electrical and Computer Engineering, Department of Bioengineering, ^¶Department of Mechanical Science and Engineering, ^#Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana—Champaign, Urbana, Illiinois 61801, United States

 School of Electrical Engineering, Korea University, Seoul, Korea

ACS Nano, Article ASAP

DOI: 10.1021/nn305400n

Publication Date (Web): December 18, 2012

Copyright © 2012 American Chemical Society

We study the electrochemistry of single layer graphene edges using a nanopore-based structure consisting of stacked graphene and Al₂O₃ dielectric layers. Nanopores, with diameters ranging from 5 to 20 nm, are formed by an electron beam sculpting process on the stacked layers. This leads to a unique edge structure which, along with the atomically thin nature of the embedded graphene electrode, demonstrates electrochemical current densities as high as 1.2 × 10⁴ A/cm². The graphene edge embedded structure offers a unique capability to study the electrochemical exchange at an individual graphene edge, isolated from the basal plane electrochemical activity. We also report ionic current modulation in the nanopore by biasing the embedded graphene terminal with respect to the electrodes in the fluid. The high electrochemical specific current density for a graphene nanopore-based device can have many applications in sensitive chemical and biological sensing, and energy storage devices.