The role of temperature on defect diffusion and nanoscale patterning in graphene

TL;DR

This study investigates how temperature influences defect diffusion and nanoscale patterning in graphene during electron beam processing, revealing temperature-dependent effects on milling, healing, and defect dynamics.

Contribution

It provides a detailed analysis of temperature effects on defect behavior in graphene under electron beam irradiation, enhancing understanding of nanoscale patterning processes.

Findings

Temperature affects milling rate and defect dynamics.

Higher temperatures promote defect diffusion and healing.

Results applicable to other 2D materials.

Abstract

Graphene is of great scientific interest due to a variety of unique properties such as ballistic transport, spin selectivity, the quantum hall effect, and other quantum properties. Nanopatterning and atomic scale modifications of graphene are expected to enable further control over its intrinsic properties, providing ways to tune the electronic properties through geometric and strain effects, introduce edge states and other local or extended topological defects, and sculpt circuit paths. The focused beam of a scanning transmission electron microscope (STEM) can be used to remove atoms, enabling milling, doping, and deposition. Utilization of a STEM as an atomic scale fabrication platform is increasing; however, a detailed understanding of beam-induced processes and the subsequent cascade of aftereffects is lacking. Here, we examine the electron beam effects on atomically clean graphene at a variety of temperatures ranging from 400 to 1000 C. We find that temperature plays a significant role in the milling rate and moderates competing processes of carbon adatom coalescence, graphene healing, and the diffusion (and recombination) of defects. The results of this work can be applied to a wider range of 2D materials and introduce better understanding of defect evolution in graphite and other bulk layered materials.