  Electrical transport in monolayer graphene on SrTiO3 (STO) thin film is
examined in order to promote gate-voltage scaling using a high-k dielectric
material. The atomically flat surface of thin STO layer epitaxially grown on
Nb-doped STO single-crystal substrate offers good adhesion between the high-k
film and graphene, resulting in nonhysteretic conductance as a function of gate
voltage at all temperatures down to 2 K. The two-terminal conductance
quantization under magnetic fields corresponding to quantum Hall states
survives up to 200 K at a magnetic field of 14 T. In addition, the substantial
shift of charge neutrality point in graphene seems to correlate with the
temperature-dependent dielectric constant of the STO thin film, and its
effective dielectric properties could be deduced from the universality of
quantum phenomena in graphene. Our experimental data prove that the operating
voltage reduction can be successfully realized due to the underlying high-k STO
thin film, without any noticeable degradation of graphene device performance.
