2D atomic crystal molecular superlattices by soft plasma intercalation.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) atomic crystal superlattices offer tunable electronic and optical properties.
• Controlling interlayer gaps and interactions in these superlattices remains a significant challenge.

Purpose of the Study:

• To introduce a novel method for tuning interlayer interactions and expanding the interlayer gap in 2D atomic crystal superlattices.
• To explore the impact of this tuning on the properties of homo- and hetero-stacked superlattices.

Main Methods:

• Utilizing soft oxygen plasma intercalation to introduce O2+ ions into the interlayer space of 2D materials.
• Forming stable molecular oxygen layers via van der Waals interactions with transition metal dichalcogenide (TMD) monolayers.
• Fabricating homo- (MoS2[O2]x) and hetero- (MoS2[O2]x/WS2[O2]x) stacked atomic crystal molecular superlattices (ACMSs).

Main Results:

• Achieved significant expansion of the interlayer gap, effectively isolating individual TMD monolayers.
• Observed a 100-fold increase in photoluminescence intensity.
• Demonstrated a 100-fold enhancement in photocurrent generation in the modified ACMSs.
• Successfully imparted exotic properties beyond those of individual monolayer TMDs.

Conclusions:

• The soft oxygen plasma intercalation offers a universal approach to tune interlayer stacking and interactions in 2D ACMSs.
• This method enables the realization of exotic superlattice properties, such as direct bandgaps, beneficial for future optoelectronics.
• The developed ACMSs show potential for advanced applications in optoelectronic devices.