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Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
Faculty of Journalism and Communications >
Thesis - Journalism and Communication >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/123456789/200
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| Title: | ABSORPTION COEFFICIENT AND DIELECTRIC FUNCTION OF DIRECT BAND GAP SILICON NANOCRYSTALLITES |
| Authors: | Hagos, Gebrehiwet |
| Advisors: | Dr. S. K. Ghoshal |
| Copyright: | 2007 |
| Date Added: | 9-Nov-2007 |
| Publisher: | Addis Ababa University |
| Abstract: | Silicon is an ubiquitous electronic material and the discovery of strong room temperature
luminescence from porous silicon in 1990 raised hopes it may find a new lease
of life in the emerging field of optoelectronics. First, the luminescence was shown to
be emitted from nanostructures in a porous silicon network. Later the same emission
was seen from silicon nanocrystallites and the concept of a silicon quantum dot
emerged. A number of different models have been proposed for the origin of the light
emission. Some involve interface states between a silicon nanocrystallite and a surrounding
shell, while others consider the effect of quantum confinement in an indirect
bandgap semiconductor.
In order to clarify the influence of morphological properties, such as size or shape, of
a silicon nanocrystallite on its optical properties, calculations of optical absorption
coefficient and dielectric function of silicon nanocrystallites as a function of effective
silicon nanocluster size (diameter) and photon energy were attempted using k.p
method.
To conclude, the work presented in this thesis gives support to the quantum confinement
effect in explaining the optical properties of band gap nano-sized silicon below
10nm, as well as highlighting the importance of calculating optical parameters of
silicon nanocrystallites to understand optical properties in the luminescence process. |
| Description: | A thesis submitted to the School of Graduate Studies
Addis Ababa University
In partial Fulfilment of the Requirements for the Degree of Master of Science in Physics |
| URI: | http://hdl.handle.net/123456789/200 |
| Appears in: | Thesis - Physics
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