From 2D to 3D: Graphene molding for transparent and flexible probes

Martin Lee,Michael Hilke,Eric Whiteway,Yuning Zhang,Carlos S Ruiz-Vargas,Walter Reisner,Thai-An Vuong,Xavier Capaldi

doi:10.1063/1.5075618

Abstract

Chemical vapor deposition (CVD) has been widely adopted as the most scalable method to obtain single layer graphene. Incorporating CVD graphene in planar devices can be performed via well-established wet transfer methods or thermal adhesive release. Nevertheless, for applications involving 3D shapes, methods adopted for planar surfaces provide only a crude solution if a continuous, tear-free, wrinkle-free graphene layer is required. In this work, we present the fabrication and characterization of Polydimethylsiloxane-supported 3D graphene probes. To accommodate 3D geometries, we perform CVD on catalysts possessing a non-trivial 3D topology, serving to mold the grown graphene to a final non-trivial 3D shape. This advance overcomes challenges observed in standard transfer processes that can result in uneven coverage, wrinkles, and tears. To demonstrate the potential of our different transfer approach, we apply it to fabricate graphene electrical probes. Graphene, due to its flexibility, transparency, and conductivity, is an ideal material with which conventional metal based probes can be replaced. In particular, with a contact impedance on the order of 10 kΩ, our graphene probes may find applications, such as in electrophysiology studies.

Highlights

Due to graphene’s unique properties, many processes have been developed to incorporate graphene, a two dimensional material, in three dimensional structures
For applications involving 3D shapes, methods adopted for planar surfaces provide only a crude solution if a continuous, tear-free, wrinkle-free graphene layer is required
We present the fabrication and characterization of Polydimethylsiloxane-supported 3D graphene probes

Summary

Introduction

Due to graphene’s unique properties, many processes have been developed to incorporate graphene, a two dimensional material, in three dimensional structures. For applications involving 3D shapes, methods adopted for planar surfaces provide only a crude solution if a continuous, tear-free, wrinkle-free graphene layer is required. Graphene is a two dimensional carbon allotrope widely known for its remarkable and versatile properties: it is flexible,[1] stretchable,[2] conductive,[3] transparent at visible wavelengths,[4] and yet extremely strong.[5] Graphene is consequentially an ideal material for flexible electronics.[6] current manufacturing processes are limited to producing flat graphene samples as the catalyst that graphene is grown on is typically obtained in the form of planar substrates.[7] the transfer steps necessary to move graphene from the catalyst surface to the final device complicate the fabrication process and introduce defects from the polymer support layers.[8] The most widely used graphene transfer process[9–11] entails coating a layer of poly(-

Results

Conclusion