Defect-Free Axially Stacked GaAs/GaAsP Nanowire Quantum Dots with Strong Carrier Confinement

Area of Science:

• Materials Science
• Nanotechnology
• Quantum Physics

Background:

• Axially stacked quantum dots (QDs) in nanowires (NWs) are crucial for nanoscale quantum devices and lasers.
• Au-free growth modes for defect-free QD-NWs require further investigation for structure optimization.

Purpose of the Study:

• To investigate the defect-free growth and structure optimization of self-catalyzed GaAsP nanowires (NWs) with axial GaAs quantum dots (QDs).
• To analyze the structural properties, interface sharpness, and stability of multiple stacked QDs within a single NW.

Main Methods:

• Utilized a self-catalyzed, Au-free growth mode for fabricating GaAsP NWs with embedded axial GaAs QDs.
• Characterized the structural quality and interface properties of the quantum dot nanowires (QD-NWs) using advanced microscopy techniques.
• Evaluated the optical properties, including emission line width and carrier confinement, of the QD-NWs.

Main Results:

• Achieved defect-free axial GaAs QDs (NWQDs) with sharp interfaces (1.8-3.6 nm) within GaAsP NWs.
• Demonstrated the ability to stack up to 50 QDs in a single NW while maintaining high structural quality.
• Observed stable emission line width (<10 meV at 140 K) after 6 months of ambient storage, deep carrier confinement (~90 meV), and large exciton-biexciton splitting (~11 meV).

Conclusions:

• The Au-free self-catalyzed growth mode enables high-quality, defect-free axially stacked QD-NWs.
• These QD-NWs exhibit exceptional stability and promising optical properties for advanced quantum applications.
• The findings provide a foundation for developing high-performance, CMOS-compatible axially stacked NWQD devices.