A Scalable Method for Thickness and Lateral Engineering of 2D Materials.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• The physical properties of two-dimensional (2D) materials are layer-dependent.
• Precise control over 2D material thickness is crucial for device applications.
• Existing methods for atomic layer precision thinning are limited in scope and scalability.

Purpose of the Study:

• To present a simple, scalable, and widely applicable method for layer-by-layer thinning of 2D materials.
• To demonstrate the method's effectiveness on germanium pnictides and chalcogenides.
• To support the development of 2D material-based electronic and optoelectronic devices.

Main Methods:

• A selective oxidation/etching process targeting the topmost layers of 2D materials.
• Experimental characterization using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and X-ray diffraction (XRD).
• First-principles simulations to elucidate the oxidation mechanism.

Main Results:

• Successful demonstration of continuous layer-by-layer thinning on germanium arsenide (GeAs), germanium sulfide (GeS), and germanium disulfide (GeS₂).
• Validation of the method's scalability and applicability to a broad class of 2D materials.
• Demonstration of precise patterning capabilities when combined with lithography.

Conclusions:

• The developed oxidation/etching method offers precise control over 2D material thickness.
• This technique is adaptable to various 2D materials by selecting appropriate reagents.
• The method facilitates advanced applications in electronics and optoelectronics requiring tailored material properties.