Improvement of Performance of HfS_2 Transistors Using a Self-Assembled Monolayer as Gate Dielectric

This work details a study based on HfS_2 transistors utilizing an n-octadecylphosphonic acid-based self-assembled monolayer (SAM) as the gate dielectric. The fabrication of the SAM-based two-dimensional (2D) material transistor is simple and can be used to improve the quality of the interface of air-sensitive 2D materials. In comparison to HfS_2 transistors utilizing a conventional Al_2O_3 gate insulator by atomic layer deposition, HfS_2 transistors utilizing an SAM as the gate dielectric can reduce the operation region from 4 V to 2 V, enhance the field-effect mobility from 0.03 cm^2/Vs to 0.75 cm^2/Vs, improve the sub-threshold swing from 404 mV/dec to 156 mV/dec, and optimize the hysteresis to 0.03 V, thus demonstrating improved quality of the semiconductor/insulator interface.