A Molecular Coordination Strategy for Regulating the Interface of MoS₂ Field Effect Transistors

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Chemically modifying two-dimensional transition metal dichalcogenides (TMDs) is crucial for tuning their electronic and optoelectronic properties.
• Existing methods often damage the crystal structure of monolayer TMDs during organic molecule attachment.
• Developing nondestructive chemical modification strategies for TMDs is a significant challenge.

Purpose of the Study:

• To develop a facile and nondestructive route for chemically modifying monolayer molybdenum disulfide (MoS2).
• To investigate the effects of coordinative bonding of organic molecules on MoS2 crystal structure and electronic properties.
• To explore the potential of this method for improving the performance of MoS2-based electronic devices.

Main Methods:

• Synthesized two isomeric molecules (LA2 and LA5) containing catechol and 1,10-phenanthroline (Phen) groups.
• Utilized coordinative bonding between Mo atoms in defect states of monolayer MoS2 (1L-MoS2) and the designed molecules.
• Employed theoretical calculations and experimental characterization, including field-effect transistor (FET) fabrication and testing.

Main Results:

• Coordinative attachment of organic molecules via Mo atoms proved to be nondestructive to the 1L-MoS2 crystal structure.
• The strategy effectively repaired sulfur vacancies, passivated defects, and induced stable n-doping.
• FETs based on modified 1L-MoS2 exhibited high electron mobilities (up to 120.3 cm^2 V^-1 s^-1) and excellent current on/off ratios (>10^9).

Conclusions:

• Coordinative bonding offers a general and effective method for the nondestructive chemical modification of TMDs.
• This approach significantly enhances the electronic properties and device performance of 1L-MoS2.
• The developed strategy holds promise for advancing the application of TMDs in electronics and optoelectronics.