Direct Evidence of Electronic Interaction at the Atomic-Layer-Deposited MoS₂ Monolayer/SiO₂ Interface

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Molybdenum disulfide (MoS₂) is a 2D material with promising electronic properties.
• Understanding the interface effects on MoS₂ electronic structure is crucial for device applications.
• Atomic-layer-deposited MoS₂ on SiO₂ is a common heterostructure.

Purpose of the Study:

• To investigate the electronic structure of MoS₂ monolayer on SiO₂.
• To analyze the influence of substrate interactions on MoS₂ electronic properties.
• To elucidate the role of van der Waals interactions at the MoS₂-SiO₂ interface.

Main Methods:

• X-ray absorption spectroscopy (XAS) with angle-dependent measurements.
• Synchrotron X-ray photoelectron spectroscopy (XPS) with photon-energy-dependent measurements.
• Ab initio electronic structure simulations for spectral analysis.

Main Results:

• Experimental XAS and XPS spectra of MoS₂/SiO₂ differ from ideal free-standing MoS₂.
• Distinct spectral features are attributed to sulfur-oxygen van der Waals (vdW) interactions.
• Simulations show good agreement with experimental data, confirming vdW interaction effects.

Conclusions:

• Van der Waals interactions between MoS₂ and SiO₂ significantly influence the electronic structure.
• A substantial electronic interaction exists at the MoS₂-SiO₂ interface.
• These findings are essential for designing and optimizing MoS₂-based electronic devices.