Selective Chemical Modulation of Interlayer Excitons in Atomically Thin Heterostructures.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Atomically thin transition metal dichalcogenide (TMDC) heterostructures exhibit strongly bound interlayer excitons (X_Is).
• These X_Is are promising for spin-valleytronics and excitonic devices, but require methods for probing and control.

Purpose of the Study:

• To introduce a versatile chemical method for selectively tailoring interlayer excitons in TMDC heterostructures.
• To investigate the impact of organic layers on X_I photoluminescence in WSe₂/MoS₂ heterostructures.

Main Methods:

• Formation of uniform organic layers on WSe₂/MoS₂ heterostructures.
• Selective application of organic layers to either side of the TMDC/TMDC heterostructure.
• Analysis of photoluminescence modulation and underlying mechanisms (charge transfer vs. p-doping).

Main Results:

• Uniform organic layers can either preserve or quench X_I photoluminescence.
• Interlayer emission can be modulated differently based on the organic layer's position.
• Selective photoinduced charge transfer dominates over dark-state p-doping effects.

Conclusions:

• The study provides critical insights into interlayer excitons at TMDC/TMDC heterointerfaces.
• A versatile chemical approach is established for selectively tailoring X_Is for optoelectronic applications.