Nanowrinkles pave way to graphene semiconductors

 

Japan-based materials scientists have used scanning tunneling microscopy to 'wrinkle' graphene, and form an electronic structure that paves the way to new graphene semiconductors.

 

Researchers worldwide have been busy manipulating the properties of graphene by chemically altering its structure, but such processes can introduce defects and degrade electronic performance.

 

However, by accident, Hyunseob Lim and colleagues from Surface and Interface Science at Riken, discovered a method to induce graphene wrinkles and alter the material's electronic properties, without resorting to chemical modification.

 

As Lim puts it: "“We were attempting to grow graphene on a single crystalline nickel substrate, but in many cases we ended up creating a compound of nickel and carbon, rather than graphene."

 

"In order to resolve the problem, we tried quickly cooling the sample after a dosing with acetylene, and during that process we accidentally found small nanowrinkles, just five nanometres wide, in the sample,” he says.

 

Using scanning tunneling microscopy and spectroscopy, the researchers imaged these nanowrinkles, and detected bandgap opening in the structures, which they believe were caused by electron confinement.

 

 

The researchers went onto manipulate the graphene nanowrinkles with the STM tip, inducing metallic-semiconducting-metallic junctions across the structures.

 

"We can manipulate the electronic properties of graphene by merely changing the shape of the carbon structure," he adds. "It will be exciting to see if this leads to new uses for graphene."

 

Research is published in Nature Communications.