▎ 摘　　要

The amphiphilic nature of graphene oxide (GO) is exploited as a seed layer to facilitate the ultrathin and conformal high-kappa metal oxide (MOX) deposition on defect-free epitaxial graphene (EG) by atomic layer deposition (ALD). Three different high-kappa metal oxides (Al2O3, HfO2 and TiO2) with various thicknesses (4-20 nm) were grown on ultrathin (1.5 nm) GO seed layers on EG. The quality of such dielectrics was examined by fabricating various metal-insulator-graphene (MIG) type devices. For MIG tunnel devices, on-off ratios of 10(4) and 10(3) were obtained for 4 nm Al2O3 and HfO2 dielectric layers, respectively. Additionally, no defect/trap assisted conduction behavior was observed. Graphene field effect transistors (GFETs) with bi-layer metal oxide stack (6 nm TiO2/14 nm HfO2) demonstrated a peak on-state current of 0.16 A/mm, an on-resistance of 6.8Xmm, an Ion/Ioff ratio of similar to 4, and a gate leakage current below 10 pA/mm at Vds = 1V and Vgs = 4V. Capacitance-voltage measurement of the same GFETs exhibited a low hysteresis and nearly ideal dielectric constants. These results demonstrate a simple yet cost-effective universal way of wafer-scale ultrathin high-kappa dielectrics deposition on epitaxial graphene by ALD. Published by AIP Publishing.