SiGeSn Ternaries for Efficient Group IV Heterostructure Light Emitters

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Silicon-germanium-tin (SiGeSn) alloys are promising for optoelectronic devices.
• Achieving high crystalline quality and tunable bandgaps in SiGeSn is crucial for infrared applications.

Purpose of the Study:

• To grow high-quality SiGeSn ternaries on Ge-buffered Si wafers.
• To engineer the bandgap of SiGeSn for short-wave infrared (SWIR) applications.
• To investigate the potential of SiGeSn for light-emitting diodes (LEDs) and strain-relaxed buffers.

Main Methods:

• Epitaxial growth of SiGeSn ternaries with varying Si and Sn content (up to 15 at%).
• Absorption measurements for bandgap characterization.
• Temperature-dependent photoluminescence experiments to assess light emission properties.
• Monitoring layer relaxation for buffer applications.

Main Results:

• SiGeSn ternaries grown with high crystalline quality and layer thicknesses up to 600 nm.
• Bandgap engineering achieved in the SWIR range up to 2.6 µm through stoichiometry and strain tuning.
• Materials near the indirect-to-direct bandgap transition were identified.
• Strong room temperature light emission observed from a fabricated GeSn/SiGeSn multiquantum well heterostructure LED.

Conclusions:

• SiGeSn ternaries offer tunable bandgaps for SWIR optoelectronics.
• The developed heterostructure approach shows significant potential for efficient light emitters.
• SiGeSn materials are suitable for both LEDs and strain-relaxed buffer applications.