A Light-Hole Germanium Quantum Well on Silicon

Area of Science:

• Quantum Information Science
• Materials Science
• Solid-State Physics

Background:

• Solid-state devices utilize quantum environments for quantum processors and memories.
• Engineering light-hole (LH) states is crucial for optical photon-spin interfaces but limited by material scalability.
• Current limitations hinder direct mapping of quantum information from photon qubits to spin processors.

Purpose of the Study:

• To overcome limitations in engineering light-hole states for quantum applications.
• To demonstrate a novel all-group-IV low-dimensional system for quantum information control.
• To enable scalable and manufacturable silicon-compatible platforms for quantum technologies.

Main Methods:

• Fabrication of highly tensile strained germanium quantum wells on silicon substrates.
• Utilizing strain-engineered, metastable germanium-tin alloyed buffer layers to achieve wafer-level tensile strain.
• Characterization of epitaxial heterostructures with sharp interfaces and room-temperature excitonic transitions.

Main Results:

• Demonstrated quantum wells with a light-hole ground state and high g-factor anisotropy.
• Achieved tunable splitting of hole sub-bands through controlled strain and thickness.
• Observed room-temperature excitonic transitions modulated and extended to the mid-wave infrared spectrum.
• Exhibited sharp interfaces with sub-nanometer broadening in epitaxial heterostructures.

Conclusions:

• The developed germanium quantum well system offers new control over hole states in a silicon-compatible platform.
• This approach enables selective confinement of light-hole states and controllable optical responses.
• The engineered quantum structures are relevant for integrated quantum communication and sensing technologies.