Poster Session 4, 2:15 PM - 3:00 PM: Campus Center Auditorium [A33]
Controlled Relative Twist Angles in Large-Grain Interlayer-Bonded Twisted Bilayer Graphene
Presenter: David Albert Stevenson
Faculty Sponsor: Christos Dimitrakopoulos
School: UMass Amherst
Research Area: Chemistry and Materials Science
ABSTRACT
Interlayer-Bonded Twisted Bilayer Graphene (IB-TBG) is a promising material for various mechanical and electrical applications. This is due to retaining a 2-dimensional structure like graphene and interlayer carbon-carbon bonds like diamond yet having novel and tunable properties based on the twist angle between its layers. Despite its promise, significant challenges in the scale-up production of IB-TBG exist primarily due to the difficulty of obtaining a sufficiently large single-crystal area for interlayer bonding.
The goal of this project is to synthesize and characterize IB-TBG with >1 cm2 single-crystal areas. Monolayer graphene is grown via chemical vapor deposition (CVD) onto a pre-annealed cm-scale copper substrate and characterized to find the structural angle of the crystal. The top is then spin-coated with a polymer solution and the copper etched away and washed to leave a polymer-layer top attached to a single-crystal and single layer graphene bottom. The sample is then set onto a silicon dioxide substrate and the polymer layer dissolved in chloroform. The process is then repeated for a 2nd graphene sample through to the etching step after which the 2nd polymer-graphene sample is pressed onto the 1st sample on silicon dioxide at the desired relative twist angle between layers. The 2nd polymer layer is then dissolved in chloroform and the 2-layer sample treated with hydrogen plasma to form the interlayer covalent bonds between the two graphene layers. This yields the large-grain IB-TBG result which is then characterized to determine bond angle and interlayer bonds.
