Fabrication of quantum dot and ring arrays by direct laser interference patterning for nanophotonics

Area of Science:

• Quantum Nanophotonics
• Semiconductor Nanostructures
• Materials Science

Background:

• Semiconductor quantum dots (QDs) and quantum rings (QRs) are crucial for single-photon and entangled-photon pair generation in quantum photonics.
• Deterministic integration of QDs into nanophotonic architectures is essential but hindered by inherent inhomogeneity and spatial randomness in self-assembled QDs.
• Reliable fabrication of uniform and ordered QD structures remains a significant challenge in epitaxy.

Purpose of the Study:

• To demonstrate a novel method for fabricating regular arrays of III-V semiconductor QDs and QRs.
• To overcome the limitations of natural inhomogeneity and spatial randomness in self-assembled QDs.
• To create a platform for advanced nanophotonic devices and quantum applications.

Main Methods:

• Utilized molecular beam epitaxy (MBE) combined with in situ direct laser interference patterning.
• Fabricated both droplet epitaxy (DE) GaAs/AlGaAs QDs and QRs, and Stranski-Krastanov (SK) InAs/GaAs QDs.
• Employed optical patterning for precise spatial arrangement of nanostructures.

Main Results:

• Successfully fabricated highly uniform and spatially ordered arrays of single III-V QDs and QRs.
• Achieved a record-narrow photoluminescence linewidth of approximately 17 meV from patterned GaAs QD arrays, indicating high optical quality.
• Demonstrated the capability to control the formation and arrangement of nanostructures.

Conclusions:

• The developed in situ laser interference patterning technique enables the deterministic fabrication of ordered QD and QR arrays.
• These precisely fabricated arrays exhibit excellent uniformity and optical properties, suitable for advanced nanophotonic applications.
• This novel approach provides a next-generation platform for functional nanophotonic devices and quantum technology development.