GaSb-based Infrared Detectors on GaAs Substrates using an Interfacial Misfit Array
Jun 17, 2013
from 02:30 PM to 04:00 PM
|Where||Engr. IV Bldg., Tesla Room 53-125|
|Contact Name||Charles J. Reyner|
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Charles J. Reyner
Advisor: Diana L. Huffaker
The ultimate promise of lattice-mismatched III/V heteroepitaxy is enabling new optical and electrical properties. Unfortunately, the strain caused by lattice-mismatched deposition typically results in high defect densities and poor device performance. A method to relieve the 7.8% strain between GaSb and GaAs is the use of an interfacial misfit array, or IMF. An IMF relieves more than 99% of the strain at the interface through a network of Lomer dislocations and results in a high quality epitaxial film. The GaSb/GaAs IMF is of particular interest, as GaSb-based materials provide the largest degree of wavelength tunability in detectors, but have a poor selection of multiplication materials for avalanche photodiode (APD) operation.
This talk will address the integration of a high bandgap, low noise GaAs-based multiplication region to a low bandgap GaSb absorber using an IMF. Both GaAs and AlGaAs APD schemes are used, providing a trade-off between carrier collection efficiency and low excess noise. Further enhancements include the placement of delta-doping near the IMF interface to increase collection efficiency. These results will enable APDs with potential wavelength tunability from visible to far infrared.
Charles J. Reyner is currently a Ph.D. candidate at the University of California, Los Angeles (UCLA), Department of Electrical Engineering. He received his M.S. degree in Optics from the University of Central Florida in 2008, and his B.S.E.E. degree from Johns Hopkins University in 2005. His research is mainly focused on molecular beam epitaxy of III/V heterostructures.