Transport properties of graphene/MoS2 heterostructure device in the low carrier density regime at cryogenic temperatures

Abstract

We explore the transport characteristics of a graphene–MoS2 heterostructure transistor in the low carrier density regime at cryogenic temperatures, specifically between 30 and 50 K. The device exhibits persistent current oscillations between two distinct levels, which we attribute to the trapping and de-trapping of charge carriers in defect states within the forbidden bandgap. These oscillations show a pronounced temperature dependence, with both the frequency and amplitude of the oscillations in current exhibiting significant changes as the temperature is varied. Furthermore, when a magnetic field is applied, the device demonstrates positive magneto current, which we associate with the suppression of weak localization effects in the carriers at low temperatures. The magneto-current and magnetoresistance are also strongly correlated with temperature, as validated by the temperature-dependent measurements. Our findings offer valuable insights into the transport properties of two-dimensional materials and devices in the low carrier density regime at cryogenic temperatures, providing a foundation for developing more robust and versatile devices for future applications.