Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition.

Hualin Zhan,David J Garrett,Nicholas V Apollo,Steven Prawer,Jiri Cervenka,Kumaravelu Ganesan,Desmond Lau

doi:10.1038/srep19822

Hualin Zhan, David J Garrett + Show 5 more

Open Access

https://doi.org/10.1038/srep19822

Copy DOI

Abstract

High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

Highlights

High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells
This paper presents a technique for one-step graphene fabrication on nanoporous anodic aluminium oxide (AAO) using plasma-enhanced chemical vapor deposition (PECVD)
To obtain graphene on amorphous carbon (a-C)-AAO samples, the sample was further annealed at the temperature of 1500 °C in vacuum

Summary

Introduction

High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Other fabrication approaches using chemical vapour deposition (CVD) have required the use of metal catalysts[13,14], which needed to be etched away to allow its use in electrochemical applications. For this reason it would be more suitable to grow graphene on porous dielectric substrates. This paper presents a technique for one-step graphene fabrication on nanoporous anodic aluminium oxide (AAO) using plasma-enhanced chemical vapor deposition (PECVD). Based on the results of the material characterization and analysis of the plasma-material interaction, it is concluded that the growth mechanism is a combination of deposition and graphitization of an ultrathin amorphous carbon layer on AAO in PECVD

Methods

Results

Discussion

Conclusion