Long triple carbon chains formation by heat treatment of graphene nanoribbon: Molecular dynamics study with revised Brenner potential

TL;DR

This study uses molecular dynamics simulations with a revised Brenner potential to explore the formation of long atomic carbon chains from heated graphene nanoribbons, revealing mechanisms for chain formation and potential nanoelectronic applications.

Contribution

It introduces a revised Brenner potential for accurate simulation of atomic chain formation in graphene nanoribbons during heat treatment.

Findings

Triple carbon chains form in zigzag GNRs at 2500 K.

Bond reorganization mechanisms involve pentagon formation.

Chain formation can be controlled for nanoelectronic devices.

Abstract

The method for production of atomic chains by heating of graphene nanoribbons (GNRs) is proposed and studied by molecular dynamics simulations. The Brenner potential is revised to adequately describe formation of atomic chains, edges and vacancy migration in graphene. A fundamentally different behavior is observed for zigzag-edge GNRs with 3 and 4 atomic rows (3 and 4-ZGNRs) at 2500 K: formation of triple, double and single carbon chains with the length of hundreds of atoms in 3-ZGNRs and edge reconstruction with only short chains and GNR width reduction in 4-ZGNRs. The chain formation mechanism in 3-ZGNRs is revealed by analysis of bond reorganization reactions and is based on the interplay of two processes. The first one is breaking of bonds between 3 zigzag atomic rows leading to triple chain formation. The second one is bond breaking within the same zigzag atomic row, which occurs predominantly through generation of pentagons with subsequent bond breaking in pentagons and results in single or double chain formation. The DFT calculations of the barriers for relevant reactions are consistent with the mechanism proposed. The possibility of chain-based nanoelectronic devices with a controllable number of chains is discussed.