Firm findings from growth of first 2D amorphous carbon

"For the first time, thanks to the discovery of this monolayer material, we're able to confirm the composition of an amorphous structure as a random network containing nanocrystallites."Sokrates Pantelides, Vanderbilt University

Plastic, glass and gels, also known as bulk amorphous materials, are everyday objects. But for researchers, these materials have long been scientific enigmas – specifically when it comes to their atomic makeup, which lacks the strict ordered, crystalline structure found in solids such as metals, diamonds and salts.

Although generally believed by the scientific community to be continuous random networks of atoms, a long-standing, fundamental question existed: are amorphous materials truly continuous random networks or do they have nanocrystallites embedded within them?

Now, there is finally an answer – thanks to a new study detailing the first successful experiments to grow, image with atomic resolution and investigate the properties of two-dimensional amorphous carbon. The study is reported by an international team of researchers, including Sokrates Pantelides, professor of physics and engineering at Vanderbilt University, in a paper in Nature.

"For the first time, thanks to the discovery of this monolayer material, we're able to confirm the composition of an amorphous structure as a random network containing nanocrystallites, lending strong evidence to one side of the primordial debate," said Pantelides. "But this work not only provides answers, it presents a physical, two-dimensional carbon material, distinct from the lauded graphene, with potentially promising applications well into our future."

Future applications for the material, according to Pantelides, could include as anti-corrosion barriers for magnetic hard discs in future computers and current collector electrodes in batteries.

The questions regarding the composition of amorphous materials persisted for years due to long-standing technological issues. These included limitations in small-scale microscopy that prevented physicists from accurately imaging three-dimensional amorphous materials at the atomic scale. And while researchers could accurately image amorphous monolayers, such monolayers were until now fabricated by using high-energy electron beams to disorder crystalline monolayers.

The first-ever stable monolayer of amorphous carbon, grown by a team led by Barbaros Özyilmaz of the National University of Singapore and imaged by the group of Kazu Suenaga at the National Institute of Advanced Industrial Science and Technology in Japan, has now resolved many of these issues.

Pantelides worked remotely with the teams in Singapore and Japan to integrate experimental data, theory and calculations. A former graduate student of Pantelides, Junhao Lin, now a post-doctoral fellow in the Suenaga group, performed the key microscopy studies. Vanderbilt post-doctoral fellow Yun-Peng Wang constructed an appropriate model and performed calculations.

The novel growth method, which uses a cold substrate and a laser to provide energy in a controlled way, yields reproducible monolayer films, and led to newfound knowledge about atomic arrangements and electrical, mechanical and optical properties. Thanks to the team's successful work and findings, the reproducible approach opens the door for research into the growth of other amorphous two-dimensional materials.

This story is adapted from material from Vanderbilt University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.