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dc.contributor.advisorGülseren, Oğuz
dc.contributor.authorBahariqushchi, Rahim
dc.date.accessioned2017-09-13T08:35:56Z
dc.date.available2017-09-13T08:35:56Z
dc.date.copyright2017-08
dc.date.issued2017-09
dc.date.submitted2017-09-12
dc.identifier.urihttp://hdl.handle.net/11693/33600
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (Ph.D.): Bilkent University, Department of Physics, İhsan Doğramacı Bilkent University, 2017.en_US
dc.descriptionIncludes bibliographical references (leaves 88-99).en_US
dc.description.abstractGroup IV semiconductor nanocrystals, namely silicon and germanium have attracted much interest in the past two decades due to their broad applications in photovoltaic, memory, optoelectronic, medical imaging and photodetection devices. Generally, there are two major features of semiconducor nanocrystals: First, spatial confinement of charge carriers which leads to the significant changes in optical and electronic properties of materials as a function of size. This effect gives the possibility to use the size and shape of the nanocrystals to tune the energy of electronic energy states. Second feature of nanocrystals, is the increased of surface area to volume ratio of the nanocrystal with reducing size. This leads to an enhanced role of the effects related to surface and interface of the nanocrystal. Furthermore, stress on the nanocrystals can lead modification of the band structure as well as in uencing the crystallization of the nanomaterials. Recent works show that measurement and control of the stress can open the way for strain engineering of the electronic band structure, thereby opening the way for new physics and applications. In this thesis, we first carry out a study on the synthesis of germanium embedded in silicon nitride and oxide matrices. In uence of the annealing method as well as germanium concentration on the formation of nanocrystals is discussed. It was found that Ge concentration and annealing play important roles in the formation of the Ge nanocrystals. With crystallographic data obtained from high resolution transmission electron microscopy, quantitative analysis of stress state of germanium nanocrystals have been done by analyzing Raman peak shift of embedded nanocrystals taking into account the phonon confinement effect. Finally, using stressors as buffer layers, superlattices of Ge nanosheets were studied to understand the effects of the stressors on the stress state of Ge nanocrystals. We demonstrate that it is possible to tune the stress on the Ge nanocrystals from compressive to tensile. Finally we showed a three dimensional Ge quantum solid that can be used in optoelectronic applications.en_US
dc.description.statementofresponsibilityby Rahim Bahariqushchi.en_US
dc.format.extentxvi, 99 leaves : illustrations (some color), charts ; 30 cmen_US
dc.language.isoen_USen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectGermanium Nanocrystalsen_US
dc.subjectDielectric Matricesen_US
dc.subjectQuantum Confinement Effecten_US
dc.subjectPhonon Confinement Modelen_US
dc.subjectPhonon Raman Spectroscopyen_US
dc.subjectHigh Resolution Transmission Electron Microscopyen_US
dc.subjectStrain Engineeringen_US
dc.subjectPhotoluminescence Spectroscopyen_US
dc.subjectSuperlatticesen_US
dc.titleSize controlled germanium nanocrystals in dielectrics : structural and optical analysis and stress evolutionen_US
dc.title.alternativeDielektrik matrislerde germanium nanokristaller : yapısal ve optik analiz ve zor evrimien_US
dc.typeThesisen_US
dc.departmentDepartment of Physicsen_US
dc.publisherBilkent Universityen_US
dc.description.degreexvi, 99 leaves : illustrations (some color), chart ; 30 cmen_US
dc.identifier.itemidB156122
dc.embargo.release2020-09-10


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