MIT engineers have discovered how to get wrinkles out of graphene — no steam required. Pure single-layer graphene is a far superior conductor than silicon and has many applications in electronics. The issue has been wrinkles in the 1-atom-thick material that hindered the flow of electrons and lessoned its uniform conductivity. Now the research team led by MIT Professor Jeehwan Kim appear to have solved this challenge.
As reported in MIT News, the team diverted from the usual technique of making graphene through CVD, or chemical vapor deposition, which often results in relatively large wrinkles. “Rather than using CVD, his (Kim’s) team produced single-crystalline graphene from a silicon carbide wafer with an atomically smooth surface, albeit with tiny, step-like wrinkles on the order of several nanometers. They then used a thin sheet of nickel to peel off the topmost graphene from the silicon carbide wafer, in a process called layer-resolved graphene transfer.”
MIT News adds: “The small wrinkles created in the LRGT method are smoothened out by oxidizing the silicon wafer onto which the graphene is to be transferred. The silicon dioxide so produced pulled the carbon atoms from the graphene onto the wafer, flattening all the wrinkles. This would not work on wrinkles that are several microns in size.”
“Per MIT News, Professor Jeehwan Kim of MIT says: ‘For graphene to play as a main semiconductor material for industry, it has to be single-domain, so that if you make millions of devices on it, the performance of the devices is the same in any location. Now we can really produce single-domain graphene at wafer scale.’”
Source: MIT News