Metamorphic Buffer Layer Platform for 1550 nm Single-Photon Sources Grown by MBE on (100) GaAs Substrate

Area of Science:

• Quantum optics
• Solid-state physics
• Materials science

Background:

• Quantum dots (QDs) are promising for single-photon sources.
• Telecommunication spectral ranges are crucial for fiber-based quantum communication.
• Metamorphic buffer layers are used to grow high-quality heterostructures.

Purpose of the Study:

• To demonstrate single-photon emission from InAs QDs in the C-band.
• To develop a GaAs-based structure suitable for fiber-based quantum communication.
• To investigate the potential of metamorphic buffer layers for enhancing QD emission.

Main Methods:

• Molecular beam epitaxy (MBE) growth of (100)-GaAs-based structures.
• Fabrication of InAs QDs on a graded In content digitally alloyed InGaAs metamorphic buffer layer.
• Characterization using time-resolved photoluminescence (TRPL).
• Implementation of GaAs/AlAs distributed Bragg reflector (DBR) for enhanced extraction efficiency.

Main Results:

• Demonstrated single-photon emission with a low multiphoton event probability of 5%.
• Achieved emission in the C-band (1530-1565 nm) compatible with standard silica fibers.
• Determined an emission lifetime of 1.95 ns, leading to a fundamental emission rate limit of 0.5 GHz.
• Utilized a graded InGaAs metamorphic buffer with up to 42% In content.

Conclusions:

• The developed GaAs-based structure with InAs QDs is a viable technology platform for non-classical light sources.
• The integration of metamorphic buffer layers and DBRs enhances QD emission efficiency.
• The results are relevant for the realization of fiber-based quantum communication systems.