Theoretical study of corundum as an ideal gate dielectric material for graphene transistors

Abstract

Using physical insights and advanced first-principles calculations, we suggest that corundum ($\ensuremath{\alpha}$-Al${}_{2}$O${}_{3}$) is an ideal gate dielectric material for graphene transistors. Clean interface exists between graphene and Al-terminated (or hydroxylated) Al${}_{2}$O${}_{3}$ and the valence-band offsets for these systems are large enough to create an injection barrier. Remarkably, a band gap of $\ensuremath{\sim}$180 meV can be induced in a graphene layer adsorbed on an Al-terminated surface with an electron effective mass of $\ensuremath{\sim}$8 $\ifmmode\times\else\texttimes\fi{}$ 10${}^{\ensuremath{-}3}$$m$${}_{e}$. Moreover, the band gaps of a graphene/Al${}_{2}$O${}_{3}$ system could be tuned by an external electric field for practical applications.