Variability of electrical contact properties in multilayer MoS2 thin-film transistors

We report the variability of electrical properties of Ti contacts in back-gated multilayer MoS2 thin-film transistors based on mechanically exfoliated flakes. By measuring current–voltage characteristics from room temperature to 240 °C, we demonstrate the formation of both ohmic and Schottky contacts at the Ti–MoS2 junctions of MoS2 transistors fabricated using identical electrode materials under the same conditions. While MoS2 transistors with ohmic contacts exhibit a typical signature of band transport, those with Schottky contacts indicate thermally activated transport behavior for the given temperature range. These results provide the experimental evidence of the variability of Ti metal contacts on MoS2, highlighting the importance of understanding the variability of electronic properties of naturally occurring MoS2 for further investigation.