Realization and electrical characterization of ultrathin crystals of layered transition-metal dichalcogenides

Ultrathin crystals of the layered transition-metal dichalcogenide MoS2 (semiconducting) and TaS2 (metallic) were obtained by mechanical peeling or chemical exfoliation techniques and electrically contacted using electron-beam lithography. The MoS2 devices showed high field-effect mobility in the tens of cm2∕Vs and an on/off ratio higher than 105. The TaS2 devices remained metallic despite the fabrication process and showed an enhancement of the superconducting transition temperature and disappearance of the charge density wave phase anomaly at low temperature.