Molecule Beam Epitaxy of GeSn on III-V material substrates for Photonic Applications
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Student: Calbi Gunder
Degree: Ph.D., May 2022
Major Professor: Dr. Gregory Salamo
- Currently infrared imaging sensors are rather large and expensive which could be alleviated though research into GeSn incorporated on silicon a group IV material and other III-V substrates.
- Germanium (Ge) has higher optical absorption efficiency in a range of interest between 1.3-1.6 μm wavelengths for near infrared applications however it has an indirect bandgap, but it can be manipulated to be direct through the incorporation of Sn.
- Develop and understand the growth of GeSn through the use of MBE in order to better incorporate it into substrates.
- Through the use of MBE (Molecular Beam Epitaxy), deposit epitaxial GeSn films on Ge substrates.
- Apply this knowledge to deposition on Si and GaAs. In order to deposit on Si, may look at using a buffer layer such as Ge to reduce lattice mismatch.
- XRD data (left) shows a Sn content of 5.8% to 8.2% in the GeSn structure.
- AFM (right) shows that some Sn segregation has occurred.
- GeSn Sn segregation needs to be reduced.
- More experimentation of increasing Sn content should be conducted.
- GeSn with Ge buffer layer should be investigated on Si.
- Investigation into the reduction of Sn segregation.