Protecting graphene surfaces from contamination during the manufacturing process is a challenge being worked on at MIT currently.
The image on the right shows a graphene sheet coated with wax during the substrate-transfer step. This method drastically reduced wrinkles on the graphene’s surface compared to a traditional polymer coating (left). Courtesy of the researchers.
“Coating graphene with wax makes for a less contaminated surface during device manufacturing. By Rob Matheson | MIT News Office
To protect graphene from performance-impairing wrinkles and contaminants that mar its surface during device fabrication, MIT researchers have turned to an everyday material: wax.
Graphene is an atom-thin material that holds promise for making next-generation electronics. Researchers are exploring possibilities for using the exotic material in circuits for flexible electronics and quantum computers, and in a variety of other devices.
But removing the fragile material from the substrate it’s grown on and transferring it to a new substrate is particularly challenging. Traditional methods encase the graphene in a polymer that protects against breakage but also introduces defects and particles onto graphene’s surface. These interrupt electrical flow and stifle performance.
In a paper published in Nature Communications, the researchers describe a fabrication technique that applies a wax coating to a graphene sheet and heats it up. Heat causes the wax to expand, which smooths out the graphene to reduce wrinkles. Moreover, the coating can be washed away without leaving behind much residue.
In experiments, the researchers’ wax-coated graphene performed four times better than graphene made with a traditional polymer-protecting layer. Performance, in this case, is measured in “electron mobility” — meaning how fast electrons move across a material’s surface — which is hindered by surface defects.”
Protecting graphene surfaces with wax looks to be an ideal approach but research continues.
Read full story at Smoothing out the wrinkles in graphene
Source: MIT News