High-mobility few-layer graphene field effect transistors fabricated on epitaxial ferroelectric gate oxides

The carrier mobility μ of few-layer graphene (FLG) field-effect transistors increases tenfold when the SiO2 substrate is replaced by single-crystal epitaxial Pb(Zr0.2Ti0.8)O3 (PZT). In the electron-only regime of the FLG, μ reaches 7×104cm2/Vs at 300 K for n=2.4×1012/cm2, 70% of the intrinsic limit set by longitudinal acoustic (LA) phonons; it increases to 1.4×105cm2/Vs at low temperature. The temperature-dependent resistivity ρ(T) reveals a clear signature of LA phonon scattering, yielding a deformation potential D=7.8±0.5eV.