Subthreshold swings below 60 mV/dec in three-terminal nanojunctions at room temperature

Subthreshold swings below the thermal limit of 60 mV/dec are demonstrated in a three-terminal nanojunction (TTJ) at room temperature. The T-shaped TTJ with a 50 nm wide center branch was based on a modulation-doped GaAs/AlGaAs heterostructure and was defined by electron-beam lithography and wet chemical etching. Operated as in-plane gated field-effect transistor, transistor characteristics were demonstrated. Efficient switching with subthreshold swings smaller than 40 mV/dec was observed. These findings are attributed to a dynamic gate capacitance which improves the switching properties of the device significantly.