Anomalous hysteresis below 1 K in the transfer characteristics of MoS2 field effect transistors

Abstract

Recent studies on single- and multilayer molybdenum disulfide (MoS2) devices have revealed their promising characteristics as semiconductor devices. Understanding the transport properties at metal/MoS2 interfaces may be crucial for their implementation. In this study, we measured the electrical characteristics of field effect transistors (FETs) with a MoS2 channel from room temperature to 30 mK. A high on/off ratio (up to 107 at 1 K) was observed at all temperatures. Below 1 K, we observed for the first time an anomalously large hysteresis in the transfer characteristics of the MoS2 FET. We hypothesize that this hysteresis results from the slow injection of electrons via quantum tunneling through the Schottky barrier at the contacts. The size of the hysteresis increased with increase in the scan rate of the gate voltage, which is consistent with the possibility of slow injection of electrons.