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Dissertation
Modulation doped field-effect photodetectors
Doctor of Philosophy (Ph.D.), Drexel University
1995
DOI:
https://doi.org/10.17918/00010352
Abstract
The dissertation is concerned with the modeling and characterization of MODFETs (Modulation Doped Field-Effect Transistors) as photodetectors. Analytical derivation revealed that the dominant photodetection mechanism in the devices is the internal photovoltaic effect, caused by hole accumulation in the GaAs layer. The illumination acts as an additional terminal, producing a shift in the gate to source bias point, through which the device can be controlled. The MODFET photoresponse is characterized by a logarithmic dependence on light intensity and extremely high optical gain at low optical power levels. A responsivity in excess of 105 A/W was measured. The response speed of currently available devices is limited to the MHz range. Several device structures, designed to extend the electrical bandwidth while preserving gain over conventional photodiodes, are proposed. The experimentally observed negative photoresponse mechanism is explained and the optical control of a MODFET oscillator is demonstrated.
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Details
- Title
- Modulation doped field-effect photodetectors
- Creators
- Murilo Araujo Romero
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xv, 151 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Engineering (1970-2026); Drexel University
- Other Identifier
- 991021889072504721