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Published on: April 28, 2016
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Stimulated Raman Scattering in Ge Nanowires
Masiar Sistani1, Maximilian G Bartmann1, Nicholas A Güsken2
1Technische Universität Wien, Institute of Solid State Electronics, Vienna 1040, Austria.
Summary
Researchers developed novel group-IV Germanium (Ge) nanowire heterostructures for efficient Raman lasers. These integrated nanoscale devices show potential for low-power, on-chip light sources compatible with CMOS technology.
Area of Science:
- Photonics and optoelectronics
- Materials science
- Nanotechnology
Background:
- Group-IV materials like Silicon (Si) and Germanium (Ge) are crucial for photonic components.
- Their indirect band gaps hinder the development of efficient light-emitting diodes and lasers.
- Existing Raman lasers using Si and Ge suffer from low quantum yield, requiring large footprints and high thresholds.
Purpose of the Study:
- To investigate stimulated Raman scattering (SRS) in novel Germanium nanowire (NW) heterostructures.
- To explore the potential of these structures for integrated, energy-efficient Raman lasers.
- To overcome limitations of current group-IV based light sources.
Main Methods:
- Fabrication of axial Aluminum-Germanium-Aluminum (Al-Ge-Al) NW heterostructures.
- Integration of Ge segments within monocrystalline Aluminum (c-Al) mirrors.
- Characterization of optical mode resonances and SRS thresholds in nanocavities.
Main Results:
- Demonstrated self-assembled Ge nanostructures (nanowires, nanodots, nanodiscs) within c-Al mirrors.
- Achieved low stimulated Raman scattering thresholds as low as 60 kW/cm² due to optical confinement and heat dissipation.
- Established abrupt metal-semiconductor interfaces crucial for device performance.
Conclusions:
- The developed Al-Ge-Al NW heterostructures offer a promising platform for nanoscale, low-power group-IV Raman lasers.
- This work paves the way for monolithically integrated, CMOS-compatible light sources.
- Efficient heat dissipation and optical confinement are key to achieving low SRS thresholds.
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