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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2084

Authors: Adem, Beriso
Advisors: Dr. S. K. Ghoshal
Copyright: Jun-2010
Date Added: 2-May-2012
Publisher: AAU
Abstract: Both nanocrystalline and nanoporous silicon shows interesting optical and light emission properties. As the system size goes to nanoscale the optical band gap, radiative transitions, oscillator strength, absorption coefficient and dielectric function increases. The nanosilicon shows unusual optical properties which have tremendous importance for nanophotonics and optoelectronic applications. The purpose of the thesis is to study the light emission and optical behavior of nanoporous silicon cluster (quantum dot) with varying porosity and oxygen as well as hydrogen at the surface. We examine these properties combining k.p perturbation method and surface state model. In order to clarify the morphological effects such as size, surface passivation and porosity level of a nanoporous silicon cluster on its optical properties, calculation of optical absorption coefficient, dielectric function and oscillator strength of porous silicon nanoclusters as a function of size (diameter) through energy gap is discussed using k.p method. The effects of nanoparticles size along with surface passivation and porosity level on optical band gap have also been investigated and compared with experiment. The porosity and surface effects are incorporated through some empirical parameters c and α in our model. Furthermore, we examine the main factors that causes photoluminescence peak to shift towards left or to the smaller wavelength of visible spectrum (blue shifted). Our results are in conformity with some other experimental and theoretical findings. We also present some of the important applications of silicon nanostructures and provide a control mechanism for light emission through our investigation.
URI: http://hdl.handle.net/123456789/2084
Appears in:Thesis - Physics

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