Dry graphene transfer print to polystyrene and ultra-high molecular weight polyethylene ¿ detailed chemical, structural, morphological and electrical characterization
Evegeniya Lock, Dean M. DeLongchamp, Scott Schmucker, Blake Simpkins, Matthew Laskoski, Shawn Mulvaney, Daniel R. Hines, Mira Baraket, Sandra Hernandez, Jeremy Robinson, Paul Sheehan, Cherno Jaye, Daniel A. Fischer, Scott Walton
In this paper we apply a transfer print approach that relies on differential adhesion to remove graphene from Cu foil to polystyrene (PS) and ultra-high molecular weight polyethylene (UHMW PE) without etching of the metal foil. The polymer surfaces are prepared using plasma functionalization followed by N-ethylamino-4-azidotetrafluorobenzoate (TFPA) deposition. Then, the graphene on Cu foil and the TFPA coated polymers are pressed at elevated temperature and mild pressure, and are separated by peeled off the Cu foil. No additional processing is applied. We perform detailed chemical, structural, morphological and electrical characterization of PS and UHMW PE before and after transfer print utilizing a suite of complementary surface analysis techniques including X-ray Photoelectron Spectroscopy (XPS), Near Edge X-ray Absorption Fine Structure (NEXAFS) and Raman spectroscopies and Atomic Force Microscopy (AFM). Charge carrier density and mobility of the transferred graphene are determined using Hall effect measurements. We find that graphenes electrical properties are preserved and comparable to those of graphene on SiO2/Si. We attribute this result to the dilute distribution of TFPA molecules. Furthermore, we find that modulation of TFPA attachment to PS and UHMW PE leads to different TFPA-layer microstructure and thus to different amount of functional azide groups available for formation of carbene bonds with graphene. This results in modulation of the graphenes compressive strain, doping and mobility.