Restorative Effects of Low‐Temperature Post‐Sulfur Annealing on Device Performance of Monolayer MoS ₂ Transistors for NMOS Inverters

Abstract The restorative effects of sulfur (S)‐passivation through low‐temperature (160 °C) post‐S annealing on the performance and stability of monolayer molybdenum disulfide (MoS ₂ ) field‐effect transistors (FETs) are investigated. S‐passivation suppresses S vacancies in the monolayer MoS ₂ channel, restoring its intrinsic electrical and material properties and leading to enhancements in field‐effect mobility from 8 to 95 cm ⁻² V ⁻¹ s ⁻¹ and subthreshold swing from 0.21 to 0.10 V dec ⁻¹ . Hole‐trapping associated with S vacancies results in the instability of the MoS ₂ FETs under a negative bias stress, whereas S interstitials acting as electron trap states contribute to the instability of the S‐passivated MoS ₂ FETs under a positive bias stress. The effects of S‐vacancy suppression on the charge‐transport properties of the MoS ₂ FETs are assessed by analyzing their activation energies and densities of states based on the reduction in defect states by S‐passivation. An N‐channel metal‐oxide semiconductor inverter consisting of the S‐passivated MoS ₂ FETs exhibiting improved voltage gains is demonstrated for the first time, indicating its potential application in logic circuits based on monolayer transition‐metal dichalcogenides.