Document Type Master's Dissertation Author Haile, Kibreab Mebrahtom URN etd-04262005-121141 Document Title An optical investigation of implantation damage as GaAs superlattices Degree MSc Department Physics Supervisor
Advisor Name Title Prof D J Brink Committee Chair Keywords
- superlattices as materials
- hydrogen ion concentration
- raman effect
- doped semiconductor superlattices
Date 2004-04-20 Availability unrestricted AbstractIn this work tunability, implantation damage and recovery of GaAs doping superlattices implanted with hydrogen ions were studied. The applicability of two models of the optical properties of semiconductors was also investigated. GaAs doping superlattices were implanted with 0.5 MeV hydrogen ions at doses of 1012 cm-2, 1014 cm-2 and 1016 cm-2. This gradually modifies their optical characteristics from superlattice behaviour to something resembling the bulk material and beyond. Such a processing technique therefore provides a convenient way of tuning the optical properties of a superlattice semi-permanently. A combined result of ellipsometry and near infrared reflectance measurements showed that a single effective oscillator as well as a more advanced three-parameter model could be applied to the virgin and ion-implanted doping superlattices. This allowed us to determine the dose dependent effective band gap as well as other model parameters. Photoluminescence as well as normal and resonance Raman techniques were applied to study hydrogen ion implantation damage and its recovery. These techniques showed that implantation damage could be reversed to a large extent by a simple thermal annealing step.
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Please cite as follows:
Haile, KM 2004, An optical investigation of implantation damage in GaAs superlattices, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-04262005-121141/ >
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