Method for Transferring High-Mobility CVD-Grown Graphene with Perfluoropolymers
Abstract
The transfer of graphene grown by chemical vapor deposition (CVD) using amorphous polymers represents a widely implemented method for graphene-based electronic device fabrication. However, the most commonly used polymer, poly(methyl methacrylate) (PMMA), leaves a residue on the graphene that limits the mobility. Here we report a method for graphene transfer and patterning that employs a perfluoropolymer---Hyflon---as a transfer handle and to protect graphene against contamination from photoresists or other polymers. CVD-grown graphene transferred this way onto LaAlO3/SrTiO3 heterostructures is atomically clean, with high mobility (~30,000 cm2V-1s-1) near the Dirac point at 2 K and clear, quantized Hall and magneto-resistance. Local control of the LaAlO3/SrTiO3 interfacial metal-insulator transition---through the graphene---is preserved with this transfer method. The use of perfluoropolymers such as Hyflon with CVD-grown graphene and other 2D materials can readily be implemented with other polymers or photoresists.