Highly Aligned Polymeric Nanowire Etch-Mask Lithography Enabling the Integration of Graphene Nanoribbon Transistors.

Sangheon Jeon,Wan Sik Hwang,Jeonghwa Jeong,Suck Won Hong,Pyunghwa Han

doi:10.3390/nano11010033

Abstract

Graphene nanoribbons are a greatly intriguing form of nanomaterials owing to their unique properties that overcome the limitations associated with a zero bandgap of two-dimensional graphene at room temperature. Thus, the fabrication of graphene nanoribbons has garnered much attention for building high-performance field-effect transistors. Consequently, various methodologies reported previously have brought significant progress in the development of highly ordered graphene nanoribbons. Nonetheless, easy control in spatial arrangement and alignment of graphene nanoribbons on a large scale is still limited. In this study, we explored a facile, yet effective method for the fabrication of graphene nanoribbons by employing orientationally controlled electrospun polymeric nanowire etch-mask. We started with a thermal chemical vapor deposition process to prepare graphene monolayer, which was conveniently transferred onto a receiving substrate for electrospun polymer nanowires. The polymeric nanowires act as a robust etching barrier underlying graphene sheets to harvest arrays of the graphene nanoribbons. On varying the parametric control in the process, the size, morphology, and width of electrospun polymer nanowires were easily manipulated. Upon O2 plasma etching, highly aligned arrays of graphene nanoribbons were produced, and the sacrificial polymeric nanowires were completely removed. The graphene nanoribbons were used to implement field-effect transistors in a bottom-gated configuration. Such approaches could realistically yield a relatively improved current on–off ratio of ~30 higher than those associated with the usual micro-ribbon strategy, with the clear potential to realize reproducible high-performance devices.

Highlights

Graphene [1,2,3,4] exhibits far superior charge mobility (>250,000 cm2 V−1 s−1 ) which has been exploited to boost the performance of futuristic semiconductor electronic devices for a wide range of applications such as field-effect transistors (FETs) [5,6,7,8], sensors [9,10], supercapacitors [11,12], and nonvolatile memory [13,14]
A chemical vapor deposition (CVD)-grown monolayer graphene sheet was transferred onto the prepared electrode/SiO2 /Si substrate, assisted by the thermal release tape or typical spin-casted polymer film [39]
Detailed characterization of the GNRs by atomic force microscopy (AFM), scanning electron microscope (SEM), and electrical measurements on single- and multi-channel devices reveal the key features of the related properties of the GNR arrays

Summary

Introduction

Graphene [1,2,3,4] exhibits far superior charge mobility (>250,000 cm V−1 s−1 ) which has been exploited to boost the performance of futuristic semiconductor electronic devices for a wide range of applications such as field-effect transistors (FETs) [5,6,7,8], sensors [9,10], supercapacitors [11,12], and nonvolatile memory [13,14]. The zigzagedge configuration in GNRs possesses localized edge states that can spin-polarized to find application in spintronic devices such as spin valves [27], whereas the armchair-edge structure has non-magnetic semiconducting features with relatively larger bandgaps that increases with decreasing ribbon-width [28]. Based on the theoretical and experimental results, the extension of graphene films to GNRs with high aspect ratios promises a value-added form of graphene by opening bandgap in quantum confinement of charge carriers, leading to the semiconducting nanomaterial. A bandgap opening is still challenging because the width and the edge structure of GNRs should be controlled separately to determine the electronic properties of the devices built with the GNRs [29]

Methods

Results

Conclusion