Diamonds offer brilliant solution to growing graphene

20 Sep 2016

Former Argonne postdoctoral researcher Diana Berman and Argonne nanoscientist Anirudha Sumant with a sample of their new graphene. Image: Wes Agresta/Argonne National Laboratory

Diamonds are a graphene manufacturer’s best friend, at least according to new research that shows using a synthetic diamond material can create graphene with fewer impurities at a reduced cost.

Those working within the materials science field wax lyrically about the potential for graphene as a ‘wonder material’ capable of revolutionising everything from consumer tech to medical devices.

But, before we can reach that stage, we still need to iron out a few problems. Most notably, reducing the cost it takes to manufacture it, and the limitations of the purity of the atom-thick material.

Future Human

That is where researchers from the Argonne National laboratory – a lab run by the US Department of Energy – come in with a new solution that could solve both issues.

Based on years of research into lab-created ultrananocrystalline diamond (UNCD), the team led by Anirudha Sumant used the material’s abundance of carbon atoms as the surface on which to rapidly grow graphene sheets.

To put the speed of growth into perspective, it takes less than one minute to grow graphene using UNCD, whereas typical graphene growth could take up to a few hours.

Previous methods of growing graphene also introduce impurities during the etching process through the use of acid and extra polymers that negatively affect its electronic properties.

At first glance, another member of the research team, Dianna Berman, said their graphene far exceeded expectations.

‘You never see such a uniform, smooth surface’

“When I first looked at the [scanning electron micrograph] and saw this nice, uniform, very complete layer, it was amazing,” Berman said.

“I’d been dealing with all these different techniques of growing graphene, and you never see such a uniform, smooth surface.”

In terms of cost reduction, the fact this graphene is developed using silicon carbide as a substrate, the cost of a graphene wafer of between three and four inches reduces by over half, from $1,200 to $500.

As with any new breakthrough, the team from the Argonne lab has said it will now try to fine-tune the graphene growing process by tweaking the temperature used to catalyse the reaction.

This will alter the thickness of the UNCD substrate and metal film that grows the graphene, thereby allowing the team to better study the physics behind the reaction.

“We’re trying to tune this more carefully to have a better understanding of which conditions lead to what quality of graphene we’re seeing,” Berman said.

The team’s research has been published in Nature Communications.

Colm Gorey was a senior journalist with Silicon Republic