Direct comparison of ohmic contact properties between graphene and metal source/drain electrodes

In this study, we directly compared the Ohmic contact properties between graphene and Ag source/drain (S/D) electrodes at the exactly same MoS 2 FET device. In order to compare Ohmic contact properties of graphene and Ag electrodes on the same MoS 2 nanoflake, graphene S/D electrodes were fabricated on MoS 2 active channel and the electrical properties were investigated as a first group. After then, the graphene electrodes were fully covered by Ag S/D electrodes as a control group. Although graphene and Ag have similar workfunctions of ~ 4.5 eV, the graphene S/D FET shows higher ON and lower OFF drain current ( I ON / I OFF of ~ 10 6 ) than that of Ag S/D FET ( I ON / I OFF of ~ 10 2 ), which comes from the Fermi energy level modulation effect of graphene. In addition, the non-classical asymmetric transistor was investigated by constructing the graphene as a source and Ag as s drain in MoS 2 FET application, and it showed the gate tunable diode-like behavior and the excellent maximum photo-sensitivity of ~ 10 5 under the green light (520 nm) as well.