Nanoscale Trapping of Interlayer Excitons in a 2D Semiconductor Heterostructure

Area of Science:

• Quantum Information Science
• Condensed Matter Physics
• Materials Science

Background:

• Deterministic placement of single excitons is essential for quantum technologies.
• MoSe₂-WSe₂ heterostructures offer tunable energies and spin-valley physics for quantum applications.
• Existing trapping methods lack deterministic placement and energy tunability.

Purpose of the Study:

• To develop a method for deterministic trapping of spatially indirect interlayer excitons (IXs).
• To achieve precise control over IX energy and confinement for quantum information processing.
• To overcome limitations of previous IX trapping techniques.

Main Methods:

• Utilized a nanopatterned graphene gate to generate a sharp electric field near MoSe₂-WSe₂ heterostructures.
• Exploited the dipole interaction between IXs and the electric field to create nanoscale traps (∼20 nm).
• Investigated electric-field-dependent energy shifts, power saturation, and lifetime changes of trapped IXs.

Main Results:

• Demonstrated strong spatial confinement of IXs within the ∼20 nm electric-field-induced traps.
• Observed predicted electric-field-dependent energy shifts and saturation at low excitation power.
• Measured increased IX lifetimes, indicating enhanced confinement and reduced non-radiative decay.

Conclusions:

• The nanopatterned graphene gate architecture enables deterministic trapping of IXs.
• This approach is a significant step toward scalable quantum technologies utilizing single IXs.
• The demonstrated technique offers precise control over IX properties for quantum information processing.