Modulating the Electronic Properties of Au-MoS₂ Interfaces Using Functionalized Self-Assembled Monolayers.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Molybdenum disulfide (MoS₂), a transition-metal dichalcogenide, is crucial for electronic devices and sensors.
• High contact resistance between metal electrodes and MoS₂ layers hinders device performance.
• Functionalized alkanethiolate self-assembled monolayers (SAMs) offer a route to modify interfacial properties.

Purpose of the Study:

• To investigate the modification of gold-molybdenum disulfide (Au-MoS₂) contact properties.
• To understand how functionalized SAMs influence the electronic characteristics of the Au-MoS₂ interface.
• To demonstrate site-selective deposition of MoS₂ using patterned SAMs.

Main Methods:

• Utilized Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) to analyze interfacial modifications.
• Employed functionalized alkanethiolate SAMs with varying terminal groups (-CH₃, -CO₂C₆F₅, -OH, -COOH).
• Investigated the interaction between both 2H and 1T phases of MoS₂ with the gold substrate.

Main Results:

• Confirmed strong interactions between both 2H and 1T MoS₂ phases and the gold substrate.
• Demonstrated that the dipole moment of the alkanethiolate SAMs effectively mediates the interface's electronic properties.
• Achieved site-selective deposition of 2H and 1T MoS₂ on micropatterned SAMs.

Conclusions:

• Functionalized SAMs are effective in tuning the electronic properties of Au-MoS₂ contacts.
• The dipole moment of SAMs plays a critical role in mediating interfacial electronic behavior.
• This approach enables the fabrication of patterned MoS₂ films with distinct conducting and semiconducting regions.