Abstract
Flexible transparent graphene-based field-effect transistors (Gr-FETs) were fabricated using large-Area single-layer graphene synthesized through low-pressure chemical vapor deposition on a pretreated copper (Cu) foil, followed by transfer of the graphene from the Cu foil to a poly(ethylene terephthalate) (PET) substrate. The electropolishing method was adopted to smooth the surface of the Cu foil, which is a crucial factor because it affects the defect density of graphene films on the PET substrate after transfer and the electronic transport property of the graphene-based devices. The influence of the electropolishing process on the graphene properties was examined using a Raman spectroscope, a scanning electron microscope, and an optical microscope. When the electropolishing process was adopted to improve the graphene quality, the carrier mobility of the flexible transparent Gr-FETs was enhanced from 90 to 340 cm 2 /(V s). Furthermore, variation of the carrier mobility was lower than 10% when the bending radius of the flexible device was decreased from 6.0 to 1.0 cm. © 2014 American Chemical Society.