Thermally driven homonuclear-stacking phase of MoS₂ through desulfurization

Area of Science:

• Materials Science and Engineering
• Condensed Matter Physics
• Nanotechnology

Background:

• Engineering phase transitions and discovering new polymorphs are key strategies for advanced functional materials.
• Molybdenum disulfide (MoS2) is a significant transition metal dichalcogenide (TMD) with tunable electronic properties.

Purpose of the Study:

• To investigate the effects of thermally driven desulfurization on the structural and transport properties of single-crystalline MoS2.
• To elucidate the mechanism behind the observed changes in stacking order and electronic band structure.

Main Methods:

• Thermal treatment of single-crystalline MoS2 samples to induce controlled desulfurization.
• Characterization of structural changes, including stacking order, using advanced microscopy and diffraction techniques.
• Measurement of electronic transport properties and band gap reduction.

Main Results:

• Thermally driven desulfurization of MoS2 improves transport properties by reducing the band gap and inducing metallization.
• Semi-desulfurization leads to a homonuclear (AA) stacking arrangement derived from the original AA' stacking of the 2H phase.
• This AA stacking is maintained even after full desulfurization of the top layer.

Conclusions:

• Controlled desulfurization is an effective method for tuning the electronic and transport properties of MoS2.
• The study provides a fundamental explanation for the characteristic AA' stacking in the 2H phase of TMDs.
• Findings offer pathways for designing novel functional materials based on engineered phase transitions in TMDs.