Chelant Enhanced Solution Processing for Wafer Scale Synthesis of Transition Metal Dichalcogenide Thin Films

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Molybdenum disulfide (MoS2) and other 2D dichalcogenides are crucial for next-generation electronics and spintronics.
• Controlling the large-area growth of high-quality MoS2 films remains a significant challenge.
• Previous methods involved solution processing of precursors followed by thermolysis.

Purpose of the Study:

• To develop a facile and reproducible method for wafer-scale production of atomically thin MoS2 layers.
• To improve control over film uniformity, coverage, and thickness.
• To investigate the role of chelating agents in the solution processing of MoS2.

Main Methods:

• Incorporation of ethylenediaminetetraacetic acid (EDTA) as a chelating agent in dimethyl sulfoxide (DMSO).
• Solution processing of a MoS2 precursor, ammonium tetrathiomolybdate ((NH4)2MoS4), with EDTA in DMSO.
• Characterization using Raman spectroscopy, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and high-resolution scanning transmission electron microscopy (HR-STEM).

Main Results:

• The EDTA-in-DMSO method provides superior control over wafer coverage and film thickness.
• The chelating and dispersing effects of EDTA are critical for achieving uniform MoS2 films.
• Homogeneous few-layer MoS2 films were successfully grown at the wafer scale.

Conclusions:

• A novel chelant-in-solution method enables the reproducible, wafer-scale growth of high-quality MoS2.
• This advancement facilitates the potential application of MoS2 in large-area electronics and spintronics.
• The use of EDTA in DMSO offers enhanced control over 2D material synthesis.