Graphene has been spot-welded to gold on a nano-scale for the first time. This is a needed development if graphene is to ever be used in electronic devices.
Graphene, a hexagonal arrangement of carbon atoms in a layer just one atom thick, has properties which could lend themselves to use in a new generation of electronics, but devices made from the material need to attach to other hardware. Making this happen involves creating connections just 0.0000004 inches wide. This is a width equal to just a couple dozen atoms.
Researchers from Utrecht University in the Netherlands and Aalto University in Finland were able to attach tiny pieces of gold to tiny graphene nanoribbions. This was an atom-by-atom task, that required the use of advanced electronics.
"We cannot use alligator clips on the atomic scale. Using well-defined chemical bonds is the way forward for graphene nanostructures to realize their potential in future electronics," Peter Liljeroth, head of the Atomic Scale Physics group at Aalto University, said.
The researchers created this new bond by first carefully studying the graphene ribbons at an atomic scale using atomic force (AFM) and scanning tunneling microscopes (STM). In addition to the carbon atoms, graphene also contains many hydrogen atoms around the edge of the molecule. The scientists then sent a small amount of electricity into the graphene ribbons, removing one hydrogen atom from the end of the ribbon, creating a atomic-sized area where the gold contact can attach. They found that the connection they created was electrically transparent, not affecting the way electricity flows through the ribbon.
"Combined AFM and STM allows us to characterize the graphene nanostructures atom-by-atom, which is critical in understanding how the structure, the bonds with the contacts and their electrical properties are related," Ingmar Swart, STM and AFM team leader at Utrecht University, said.
Although this technology in its current state of development can not yet be used to attach graphene-based electronics to larger real-world devices, it may pave the way for devices which can accomplish the task.
Development of the technology to create graphene bonds to gold was detailed in the journal Nature Communications.