Reliable Fabrication of Graphene Nanostructure Based on e-Beam Irradiation of PMMA/Copper Composite Structure.

Kaixi Bi,Ligang Tan,Shuqi Han,Yaokai Niu,Jiliang Mu,Linyu Mei,Xiujian Chou,Wenping Geng,Wenxiao Fu,Siyuan Zhou

doi:10.3390/ma14164634

Abstract

Graphene nanostructures are widely perceived as a promising material for fundamental components; their high-performance electronic properties offer the potential for the construction of graphene nanoelectronics. Numerous researchers have paid attention to the fabrication of graphene nanostructures, based on both top-down and bottom-up approaches. However, there are still some unavoidable challenges, such as smooth edges, uniform films without folds, and accurate dimension and location control. In this work, a direct writing method was reported for the in-situ preparation of a high-resolution graphene nanostructure of controllable size (the minimum feature size is about 15 nm), which combines the advantages of e-beam lithography and copper-catalyzed growth. By using the Fourier infrared absorption test, we found that the hydrogen and oxygen elements were disappearing due to knock-on displacement and the radiolysis effect. The graphene crystal is also formed via diffusion and the local heating effect between the e-beam and copper substrate, based on the Raman spectra test. This simple process for the in-situ synthesis of graphene nanostructures has many promising potential applications, including offering a way to make nanoelectrodes, NEMS cantilever resonant structures, nanophotonic devices and so on.

Highlights

Graphene nanostructures, forming a promising 2D nanomaterial with excellent properties, have been widely studied for electronic applications, sensing, biomedicine, and other fields [1,2,3]
PMMA is a typical high-resolution positive/negative e-beam resist for nanostructure fabrication. It has many advantages in terms of long-lasting results and a good sticking ability to the target substrate surface, and it is cost-effective and highly reproducible. It can be transformed into a graphite-like material under e-beam irradiation
Considering the aim of this paper is to construct a graphene nanostructure, the copper substrate was used for fabrication, based on the Cu-catalyzed graphene growth mechanism

Summary

Introduction

Graphene nanostructures, forming a promising 2D nanomaterial with excellent properties, have been widely studied for electronic applications, sensing, biomedicine, and other fields [1,2,3]. Some graphene nanoribbons or nanodots can be prepared using the top-down approach, ensuring size and location control still has many difficulties Apart from these techniques, e-beam irradiation in-situ enables the growth of a functional graphene nanostructure in a unique high-precision preparation method, representing an advanced fabrication method in this field. Chen et al fabricated a graphite electrode by irradiating PMMA film on a SiO2/Si substrate, to construct a high-resolution graphitized nanostructure with the help of the post-annealing process [17]. PMMA film on a copper substrate was selectively irradiated with a highenergy e-beam By combining this with the subsequent high-temperature annealing process, various graphene nanostructures, including nanoribbon, dot arrays and other patterns, can be created. The few-layers graphene nanostructure formed on the copper surface with the temperature of the tube furnace cooling down to room temperature

Morphology Characterization

Material Characterization

Results and Discussion