Improvement of Performance of HfS₂ Transistors Using a Self-Assembled Monolayer as Gate Dielectric

This work details a study based on HfS₂ 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 HfS₂ transistors utilizing a conventional Al₂O₃ gate insulator by atomic layer deposition, HfS₂ transistors utilizing an SAM as the gate dielectric can reduce the operation region from 4V to 2V, enhance the field-effect mobility from 0.03 cm²/Vs to 0.75 cm²/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. (paper)