Steep-Slope Gate-Connected Atomic Threshold Switching Field-Effect Transistor with MoS2 Channel and Its Application to Infrared Detectable Phototransistors.

For next-generation electronics and optoelectronics, 2D-layered nanomaterial-based field effect transistors (FETs) have garnered attention as promising candidates owing to their remarkable properties. However, their subthreshold swings (SS) cannot be lower than 60 mV/decade owing to the limitation of the thermionic carrier injection mechanism, and it remains a major challenge in 2D-layered nanomaterial-based transistors. Here, a gate-connected MoS2 atomic threshold switching FET using a nitrogen-doped HfO2-based threshold switching (TS) device is developed. The proposed device achieves an extremely low SS of 11 mV/decade and a high on-off ratio of ≈106 by maintaining a high on-state drive current due to the steep switching of the TS device at the gate region. In particular, the proposed device can function as an infrared detectable phototransistor with excellent optical properties. The proposed device is expected to pave the way for the development of future 2D channel-based electrical and optical transistors.