Conversion of self-assembled monolayers into nanocrystalline graphene: Structure and electric transport

TL;DR

This paper presents a method to convert self-assembled monolayers into nanocrystalline graphene with tunable electrical properties, enabling scalable production of 2D carbon materials for nanoelectronics and nanobiotechnology.

Contribution

It introduces a novel electron-radiation induced process to transform SAMs into nanocrystalline graphene with controllable electrical characteristics.

Findings

Transformation causes an insulator to metal transition.

Electrical properties like conductivity and electron mobility can be tuned.

The method allows fabrication of free-standing 2D graphene on various substrates.

Abstract

Graphene-based materials have been suggested for applications ranging from nanoelectronics to nanobiotechnology. However, the realization of graphene-based technologies will require large quantities of free-standing two-dimensional (2D) carbon materials with tuneable physical and chemical properties. Bottom-up approaches via molecular self-assembly have great potential to fulfil this demand. Here, we report on the fabrication and characterization of graphene made by electron-radiation induced cross-linking of aromatic self-assembled monolayers (SAMs) and their subsequent annealing. In this process, the SAM is converted into a nanocrystalline graphene sheet with well defined thickness and arbitrary dimensions. Electric transport data demonstrate that this transformation is accompanied by an insulator to metal transition that can be utilized to control electrical properties such as conductivity, electron mobility and ambipolar electric field effect of the fabricated graphene sheets. The suggested route opens broad prospects towards the engineering of free-standing 2D carbon materials with tuneable properties on various solid substrates and on holey substrates as suspended membranes.