Nondestructive Atomic Defect Quantification of Two-Dimensional Materials and Devices.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Characterizing atomic defects in 2D semiconductors is vital for optimizing growth and device performance.
• Current defect metrology methods are often slow, destructive, or lack sufficient sensitivity.

Purpose of the Study:

• To introduce and validate lateral force microscopy (LFM) as a nondestructive technique for atomic defect characterization in 2D materials.
• To assess LFM's sensitivity and applicability across various 2D materials, substrates, and device structures.

Main Methods:

• Utilized lateral force microscopy (LFM) to map surface defects in monolayer tungsten diselenide (WSe2) and tungsten disulfide (WS2).
• Applied LFM to materials on silicon dioxide (SiO2) and sapphire substrates, as well as in WSe2 transistors.
• Compared LFM defect detection limits with conventional Raman spectroscopy.

Main Results:

• LFM successfully mapped surface defects in WSe2 and WS2 on different substrates and in transistors.
• The technique detected defect densities significantly lower than those measurable by Raman spectroscopy.
• LFM revealed higher defect densities in WSe2 transistors compared to as-grown films, indicating fabrication-induced defects.
• Demonstrated LFM's capability to detect defects in suspended and polymer-supported 2D materials.

Conclusions:

• Lateral force microscopy (LFM) is a highly sensitive, nondestructive method for atomic defect characterization in 2D semiconductors.
• LFM provides valuable insights for monitoring 2D material growth and identifying defects introduced during device fabrication.
• This technique broadens the scope of defect metrology for advanced 2D material applications.