Polytype control of MoS₂ using chemical bath deposition

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Molybdenum disulfide (MoS₂) is a crucial material with diverse applications.
• Controlling the specific crystal structure (polytype) of deposited MoS₂ films is challenging.
• Understanding polytype control is key to tailoring MoS₂ for specific electronic and catalytic properties.

Purpose of the Study:

• To develop a method for controlling molybdenum disulfide (MoS₂) polytype deposition.
• To investigate the influence of substrate surface properties on MoS₂ film formation.
• To enable the deposition of large-area MoS₂ thin films with desired polytypes.

Main Methods:

• Utilized chemical bath deposition, an aqueous technique, for MoS₂ thin film deposition at room temperature.
• Employed self-assembled monolayers (SAMs) with varying surface terminations (hydrophobic and hydrophilic) as substrates.
• Characterized the deposited MoS₂ films using Raman spectroscopy and X-ray photoelectron spectroscopy.

Main Results:

• Successfully deposited large-area MoS₂ thin films at room temperature.
• Demonstrated the ability to switch between semiconducting 2H MoS₂ and semimetallic 1T MoS₂ polytypes.
• Correlated MoS₂ polytype formation with substrate surface energy: high surface energy favors 1T, low surface energy favors 2H.

Conclusions:

• Substrate surface energy is a critical factor in controlling MoS₂ polytype deposition via chemical bath deposition.
• This method offers a general approach for depositing different MoS₂ polytypes on various substrates.
• The findings pave the way for tailored synthesis of MoS₂ materials for advanced applications.