Threading dislocation reduction in heteroepitaxial GaSb based superlattices grown on silicon
Evangelia Delli1, Mathew Bentley2,3, Niall Mulholland2
1School of Engineering, Lancaster University, Bailrigg, Lancaster, LA1 4YW, UK. evdelli@physics.auth.gr.
Scientific Reports
|June 3, 2026
Summary
Researchers developed a new method for growing high-quality gallium antimonide (GaSb) on silicon (Si). This breakthrough significantly reduces crystal defects, paving the way for advanced mid-infrared silicon photonics.
Area of Science:
- Materials Science
- Semiconductor Physics
- Photonics
Background:
- Direct epitaxial growth of gallium antimonide (GaSb) on silicon (Si) is crucial for mid-infrared (MIR) silicon photonics.
- Significant lattice mismatch and material dissimilarities cause crystal imperfections and threading dislocations, hindering device integration.
Purpose of the Study:
- To achieve high-quality GaSb epilayers on Si with significantly reduced defect density.
- To overcome the challenges associated with growing dissimilar materials for advanced photonic applications.
Main Methods:
- Utilized molecular beam epitaxy (MBE) for GaSb growth on Si.
- Implemented a novel growth strategy involving an AlSb interfacial misfit array.
- Employed a two-step GaSb growth temperature process and strained dislocation filter superlattices (DFSLs).
Main Results:
- Achieved high-quality GaSb epilayers on Si with a low defect density of 6 × 10⁶ cm⁻².
- Engineered superlattice layers to block defect propagation and prevent new defect generation.
- Observed a significant increase in photoluminescence intensity, indicating excellent crystalline quality.
Conclusions:
- The novel MBE growth procedure effectively reduces threading dislocation density in GaSb on Si.
- This advancement enables the integration of GaSb-based devices into silicon photonics platforms.
- The improved crystalline quality is vital for realizing next-generation MIR photonic devices.
