High-Mobility Few-Layer Graphene Field Effect Transistors Fabricated on Epitaxial Ferroelectric Gate Oxides

Abstract

The carrier mobility $\ensuremath{\mu}$ of few-layer graphene (FLG) field-effect transistors increases tenfold when the ${\mathrm{SiO}}_{2}$ substrate is replaced by single-crystal epitaxial $\mathrm{Pb}({\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}){\mathrm{O}}_{3}$ (PZT). In the electron-only regime of the FLG, $\ensuremath{\mu}$ reaches $7\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{V}\text{ }\mathrm{s}$ at 300 K for $n=2.4\ifmmode\times\else\texttimes\fi{}{10}^{12}/{\mathrm{cm}}^{2}$, 70% of the intrinsic limit set by longitudinal acoustic (LA) phonons; it increases to $1.4\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{V}\text{ }\mathrm{s}$ at low temperature. The temperature-dependent resistivity $\ensuremath{\rho}(T)$ reveals a clear signature of LA phonon scattering, yielding a deformation potential $D=7.8\ifmmode\pm\else\textpm\fi{}0.5\text{ }\text{ }\mathrm{eV}$.