Comparative Study between Sulfurized MoS₂ from Molybdenum and Molybdenum Trioxide Precursors for Thin-Film Device...

Two-dimensional (2D) materials have been studied as an emerging class of nanomaterials owing to their attractive properties in nearly every field of science and technology. Molybdenum disulfide (MoS₂) is one of the more promising candidates of these atomically thin 2D materials for its technological potential. The facile synthesis of MoS₂ remains a matter of broad interest. In this study, MoS₂ was synthesized by chemical vapor deposition sulfurization at various temperatures (550 °C, 650 °C, and 750 °C) of either precursor molybdenum metal (Mo) or molybdenum trioxide (MoO₃) deposited on silicon/silicon dioxide (Si/SiO₂) via e-beam evaporation. Monolayer, bilayer, and few layers sulfurized samples have been grown and verified by Raman, photoluminescence spectroscopy, XRD, XPS, and AFM. MoO₃ sulfurization provided monolayer growth in comparison to Mo sulfurization under the same conditions and precursor thicknesses. Optical microscopy showed the homogeneous nature of grown samples. A main finding of this work is that MoO₃ sulfurization produced higher quality MoS₂ as compared to those grown by an Mo precursor. Device characteristics based on monolayer MoO₃ sulfurized MoS_2- include nonvolatile resistive switching with I_on/I_off ≈ 10⁴ at a relatively low operating bias of ±1 V. In addition, field-effect transistor characteristics revealed p-type material growth with a carrier mobility ∼ 41 cm² V^-1 s^-1, which is in contrast to typically observed n-type characteristics.