Browsing Dept. of Physics - Ph.D. / Sc.D. by Issue Date
Now showing items 21-40 of 76
-
Silicon based dielectrics : growth, characterization, and applications in integrated optics
(Bilkent University, 2005)In recent years, growing attention has been paid to silicon based dielectrics, such as silicon oxynitrides, silicon nitrides, and semiconductor doped silicon oxides, all combined under the name silica on silicon technology. ... -
Decoherence in open quantum systems : a realistic approach
(Bilkent University, 2006)Decoherence mechanisms of opcu quantum systems ın intcraction with an enviromental bath is investigated using the master equation formalism. Widely used two-level approximation is questioned. -
Investigation of lateral forces in dynamic mode using combined AFM/STM
(Bilkent University, 2007)In this Ph.D. work, we constructed a ¯ber optic interferometer based non-contact Atomic Force Microscope (nc-AFM) combined with Scanning Tunneling Micro- scope(STM) to study lateral force interactions on Si(111)-(77) ... -
Spintronic properties of carbon and silicon based nanostructures
(Bilkent University, 2007)In this thesis, nanostructures which may display novel spintronic behaviors are revealed and their properties are investigated by using first-principles methods. We have concentrated on three different systems, namely ... -
Novel approaches to control the propagation of electromagnetic waves : metamaterials and photonic crystals
(Bilkent University, 2007)Applications in areas such as photonics, antennas, imaging and optics require the control of propagation of electromagnetic waves and the control of emission of electromagnetic radiation. Achievements in three key research ... -
Development of nano hall sensors for high resolution scanning hall probe microscopy
(Bilkent University, 2008) -
Entanglement in local systems
(Bilkent University, 2008)In this study, we first discuss entanglement measures and we introduce a way to construct generic entangled states of an n-level quantum system. Then we discuss entanglement as a local object. Particularly we use a ... -
Plasmonic band gap cavities
(Bilkent University, 2008)Surface plasmon polaritons (SPP’s) are trapped electromagnetic waves coupled to free electrons in metals that propagate at the metal-dielectric interfaces. Due to their surface confinement and potential in sub-wavelength ... -
Carrier dynamics in silicon and Germanium nanocrystals
(Bilkent University, 2008)This is a computational work on the Si and Ge nanocrystals (NCs) embedded in wide band gap host matrices. As the initial task, extensive ab initio work on the structural and electronic properties of various NC host ... -
Ground-state properties of ultra-cold atomic gases
(Bilkent University, 2008)After the observation of Bose-Einstein condensation, the developments in the experimental control and measurement methods provided the realization of basic models of many-body physics using dilute, ultra-cold gases. This ... -
Characterization and applications of negative-index metamaterials
(Bilkent University, 2008)Metamaterials offer novel electromagnetic properties and promising applications including negative refraction, flat-lenses, superlenses, cloaking devices. In this thesis, we characterized the negative-index metamaterials ... -
Titanium dioxide nanostructures for photocatalytic and photovoltaic applications
(Bilkent University, 2008)In this thesis, TiO2 nanostructures and their photocatalytic and photovoltaic ap- plications have been investigated by using the ¯rst-principles calculations based on density functional theory. We have concentrated on ... -
Electro-magnetic properties and phononic energy dissipation in graphene based structures
(Bilkent University, 2008)With the synthesis of a single atomic plane of graphite, namely graphene honeycomb structure, active research has been focused on the massless Dirac fermion behavior and related artifacts of the electronic bands crossing ... -
GaN/AlGaN-based UV photodetectors with performances exceeding the PMTS
(Bilkent University, 2008)The recent developments in high Al-content AlxGa1−xN material growth technology made it possible to fabricate high performance solar-blind photodetectors operating in the ultraviolet (UV) spectral region with improved receiver ... -
Many-body effects in selected two-dimensional systems
(Bilkent University, 2009)In this thesis we study many-body effects in three distinct two-dimensional systems. The two dimensional electron gas is a model system yielding to basic analytical and computational theoretical ideas of many-body physics ... -
On the strain in silicon nanocrystals
(Bilkent University, 2009)In this Thesis we present our achievements towards an understanding of atomistic strain mechanisms and interface chemistry in silicon nanocrystals. The structural control of silicon nanocrystals embedded in amorphous ... -
Entanglement : quantification via uncertainties and search among ultracold bosons in optical lattices
(Bilkent University, 2009)In the first part of the Thesis, the known measures of entanglement for finite dimensional systems are reviewed. Both the simplest case of pure states that belong to bipartite systems and more general case of mixed states ... -
Quantum entanglement and light propagation through Bose-Einstein condensate (BEC)
(Bilkent University, 2009)We investigate the optical response of coherent media, a Bose-Einstein condensate (BEC), to intense laser pump stimulations and weak probe pulse propagation. First, we adopt the coherence in sequential superradiance ... -
Quantum gases in rotating optical lattices
(Bilkent University, 2010)The thesis is structured into two main parts so as to cover bosons and fermions in rotating optical lattices separately. In the first part, after a brief introduction to ultracold atoms in optical lattices, we review the ... -
The left hand of electromagnetism : metamaterials
(Bilkent University, 2010)Metamaterials are artificial periodic structures whose electromagnetic response is solely dependent on the constituting unit cells. In the present thesis, we studied unit cell characteristics of metamaterials that has ...
