Browsing by Keywords "Silica"
Now showing items 1-20 of 46
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Analysis of strain fields in silicon nanocrystals
(American Institute of Physics, 2009)Strain has a crucial effect on the optical and electronic properties of nanostructures. We calculate the atomistic strain distribution in silicon nanocrystals up to a diameter of 3.2 nm embedded in an amorphous silicon ... -
Chalcogenide integrated hollow-core optical fibers for infrared light guidance
(Bilkent University, 2022-12)The low-loss light transmission and broad bandwidth of hollow-core negative curvature fibers (NCFs) have a variety of applications in infrared (IR) light guidance, such as chemical detection, biomedical surgery, and laser ... -
Chalcogenide microresonators tailored to distinct morphologies by the shaping of glasses on silica tapers
(OSA - The Optical Society, 2017)Production of chalcogenide (As2Se3) microresonators in sphere, loop, and bottle morphologies by the shaping of glasses at appropriate temperatures between cleaved silica tapers is reported. The quality factors exceed QS = ... -
Charging/discharging of Au (core)/silica (shell) nanoparticles as revealed by XPS
(American Chemical Society, 2005)By recording XPS spectra while applying external voltage stress to the sample rod, we can control the extent of charging developed on core-shell-type gold nanoparticles deposited on a copper substrate, in both steady-state ... -
Computational modeling of quantum-confined impact ionization in Si nanocrystals embedded in SiO2
(2007)Injected carriers from the contacts to delocalized bulk states of the oxide matrix via Fowler-Nordheim tunneling can give rise to quantum-confined impact ionization (QCII) of the nanocrystal (NC) valence electrons. This ... -
Cyclodextrin-functionalized mesostructured silica nanoparticles for removal of polycyclic aromatic hydrocarbons
(Academic Press Inc., 2017)Polycyclic aromatic hydrocarbons (PAHs) are the byproducts of the incomplete combustion of carbon-based fuels, and have high affinity towards DNA strands, ultimately exerting their carcinogenic effects. They are ... -
Cytotoxicity of multifunctional surfactant containing capped mesoporous silica nanoparticles
(Royal Society of Chemistry, 2016)This paper reports the synthesis of silica capped surfactant (cetyltrimethylammonium bromide; CTAB) and dye (Rose Bengal; RB) containing mesoporous silica nanoparticles (MSNs). Capping the pores of the surfactant containing ... -
Differential charging in SiO2/Si systems as determined by XPS
(American Chemical Society, 2004)The Si2p binding and the SiKLL kinetic energy difference between the SiO2 layer and Si substrate is shown to be influence by application of external voltage bias to the sample holder due to the differential charging as was ... -
Differential charging in x-ray photoelectron spectroscopy: a nuisance or a useful tool?
(American Chemical Society, 2003)We apply a negative bias to the sample while recording an XPS spectrum to enhance differential (positive) charging. The enhanced differential charging is due to the repulsion of stray electrons from the sample, which ... -
Femtosecond laser fabrication of fiber based optofluidic platform for flow cytometry applications
(SPIE, 2017)Miniaturized optofluidic platforms play an important role in bio-analysis, detection and diagnostic applications. The advantages of such miniaturized devices are extremely low sample requirement, low cost development and ... -
Fluorescent aerogel films for TNT sensing
(Bilkent University, 2009)Silica aerogels are unique materials with extraordinary properties such as, high porosity, large surface area and low refractive indices. Due to these properties, they can be applied to a wide range of areas including, ... -
Genetically programmed engineered cells for biomaterials synthesis
(Bilkent University, 2021-01)Several organisms can process nanomaterials and producing in various sizes and morphologies in mild conditions by utilizing specific proteins. In sea sponges, silicatein proteins play a key role in synthesizing silica ... -
Growth of Ge nanoparticles on SiO2 / Si interfaces during annealing of plasma enhanced chemical vapor deposited thin films
(Elsevier B.V., 2007)Multilayer germanosilicate (Ge:SiO2) films have been grown by plasma enhanced chemical vapor deposition. Each Ge:SiO2 layer is separated by a pure SiO2 layer. The samples were heat treated at 900 °C for 15 and 45 min. ... -
High-Q silicon-on-insulator optical rib waveguide racetrack resonators
(Optical Society of American (OSA), 2005)In this work, detailed design and realization of high quality factor (Q) racetrack resonators based on silicon-on-insulator rib waveguides are presented. Aiming to achieve critical coupling, suitable waveguide geometry is ... -
Influence of gold-silica nanoparticles on the performance of small-molecule bulk heterojunction solar cells
(Elsevier BV * North-Holland, 2015)Light trapping by gold (Au)-silica nanospheres and nanorods embedded in the active layer of small-molecule (SM) organic solar cell has been systematically compared. Nanorod significantly outperforms nanosphere because of ... -
Matrix density effect on morphology of germanium nanocrystals embedded in silicon dioxide thin films
(Materials Research Society, 2011)Flash type electronic memories are the preferred format in code storage at complex programs running on fast processors and larger media files in portable electronics due to fast write/read operations, long rewrite life, ... -
Mesoscopic model of nucleation and Ostwald ripening/stepping: Application to the silica polymorph system
(American Inst of Physics, Woodbury, NY, United States, 2000)Precipitation is modeled using a particle size distribution ~PSD! approach for the single or multiple polymorph system. A chemical kinetic-type model for the construction of the molecular clusters of each polymorph is ... -
A method of two-scale chemo-thermal-mechanical coupling for concrete
(CIMNE, 2011)The Alkali Silica Reaction(ASR) is one of the most important reasons to cause damage in cementitious constructions, which can be attributed to the expansion of hydrophilic gel produced in the reaction. In this contribution, ... -
A multiscale method to analyze the deterioration due to alkali silica reaction considering the effects of temperature and relative humidity
(International Center for Numerical Methods in Engineering, 2013)This work presents a three-dimensional multiscale framework to investigate the deterioration resulting from alkali silica reaction (ASR) in the concrete. In this contribution, 3D micro-CT scan of hardened cement paste (HCP) ... -
Nano-structured organically modified silica thin films for functional surfaces
(2011)We report a template-free sol-gel method for preparation of nanoporous ormosil thin films at ambient conditions. The thin films are coated to the surfaces by using colloidal suspensions of ormosil gels. Gels are synthesized ...
