From Point Defects in Graphene to Two-Dimensional Amorphous Carbon

TL;DR

This study demonstrates the creation of an amorphous two-dimensional carbon membrane with unique polygonal structures using electron irradiation, revealing new insights into carbon bonding and defect dynamics with potential electronic applications.

Contribution

First experimental realization of amorphous 2D carbon with polygonal arrangements, combining electron irradiation and first-principles calculations to understand defect formation and bonding.

Findings

Formation of amorphous 2D carbon with polygons including four-membered rings

Step-by-step nucleation and growth of vacancy structures

Domains exhibit a band gap suitable for electronic devices

Abstract

While crystalline two-dimensional materials have become an experimental reality during the past few years, an amorphous 2-D material has not been reported before. Here, using electron irradiation we create an sp2-hybridized one-atom-thick flat carbon membrane with a random arrangement of polygons, including four-membered carbon rings. We show how the transformation occurs step-by-step by nucleation and growth of low-energy multi-vacancy structures constructed of rotated hexagons and other polygons. Our observations, along with first-principles calculations, provide new insights to the bonding behavior of carbon and dynamics of defects in graphene. The created domains possess a band gap, which may open new possibilities for engineering graphene-based electronic devices.