Edge surfaces in lithographically textured molybdenum disulfide.

Area of Science:

• Materials Science
• Surface Science
• Catalysis

Background:

• Layered molybdenum disulfide (MoS2) is a catalytically important material.
• Conventional MoS2 crystals primarily exhibit basal plane surfaces, limiting edge-plane studies.
• Understanding surface morphology and electronic structure is crucial for optimizing catalytic activity.

Purpose of the Study:

• To investigate the surface morphology and electronic structure of molybdenum disulfide single crystals.
• To explore the catalytic potential of MoS2 edge surfaces.
• To correlate microstructuring with changes in optical and electronic properties.

Main Methods:

• Lithographic techniques were employed to micro-structure MoS2 single crystals.
• Exposing and analyzing the edge surfaces of the crystals.
• Measuring optical absorption spectra.
• Utilizing photoemission spectroscopy to analyze surface composition and defects.

Main Results:

• Microstructuring successfully exposed edge surfaces of MoS2 single crystals.
• Optical absorption at mid-gap increased by two orders of magnitude after texturing.
• Photoemission spectroscopy indicated reduced molybdenum at surface defects on edge planes.
• These findings provide insights not obtainable from conventional basal plane surfaces.

Conclusions:

• Lithographic texturing is an effective method for creating ideal MoS2 samples for surface studies.
• Exposed edge surfaces exhibit significantly altered electronic and optical properties compared to basal planes.
• The observed increase in optical absorption is linked to defect-induced changes on edge planes, enhancing catalytic potential.