Bottom-up Growth of Graphene Nanospears and Nanoribbons

TL;DR

This paper presents a novel CVD method for growing graphene nanoribbons and nanospears on copper, revealing the growth mechanisms and enabling scalable synthesis of these nanostructures.

Contribution

It introduces a vapor-liquid-solid growth mechanism for GNRs and demonstrates control over their shape by tuning hydrogen flow during synthesis.

Findings

VLS growth enables one-dimensional GNR formation.

Suppression of VSS growth leads to nanospear-shaped graphene.

Real-time observations confirm the growth mechanism.

Abstract

Graphene nanoribbons (GNRs) are considered one of the most promising materials for next generation electronics, however a reliable and controllable synthesis method is still lacking. Here, we report the CVD growth of GNRs on a copper surface and the corresponding mechanisms of growth. One-dimensional GNR growth is enabled by a vapor-liquid-solid (VLS) graphene growth guided by on-surface propagation of a liquid catalyst particle. Controlling the suppression of vapor-solid-solid (VSS) graphene growth along the width direction of the GNR by tuning the flow of H2 during growth gives rise to a spear head-shaped graphene that we term graphene nanospears (GNSs). The real-time visual and spatially resolved observations confirm the VSS growth of graphene can be fully suppressed and lead to GNR formation on Cu surface. These findings reveal key insight into the growth mechanism of graphene and open a door for achieving a facile and scalable method of synthesizing free standing GNRs.