Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

Browse

Filters

2017 - 201912020 - 20211

Settings

Subject: search.filters.subject.Silicon nitride

Search Results

Now showing 1 - 2 of 2
  • Master Thesis
    Investigation of the Silicon Nitride Coating Thickness on Silicon Wafer Substrates for Enhanced Sensitivity in Dried Nano-Droplet Analysis by Laser Induced Breakdown Spectroscopy
    (01. Izmir Institute of Technology, 2021) Durkan Kaplan, Dilara; Yalçın, Şerife Hanım
    Laser Induced Breakdown Spectroscopy (LIBS) is an atomic emission spectroscopic technique that uses laser beam to generate plasma for detection. Also, LIBS is a fast and non-destructive methodology with the advantage of no sample preparation requirement and easy usage. Surface Enhanced LIBS (SENLIBS) is recently developed version of the LIBS technique that uses some kinds of surface materials for supporting liquids and for the enhancement of LIBS signal intensity. It has been previously shown that silicon nitride coated silicon wafer substrates have some properties to enhance LIBS signal of several metal solutions by dried-droplet analysis methodology. Within the scope of this thesis study, silicon wafers coated with silicon nitride of several thicknesses were utilized for investigating the effect of coating thickness on sensitivity of the LIBS technique for liquids analysis. Heavy metals above a certain concentration have a significant negative impact on the environment and human health. In this context, the chromium, copper and lead metal liquid samples was loaded on 75 nm, 300 nm, 450 nm and 1000 nm silicon nitride coated wafers and dried, then analyzed by LIBS. As a result of this study, it was seen that the 1000 nm coating increased the LIBS signal intensity at the highest degree. The LOD value of the chromium element was improved as 0.56 pg, the lead element as 0.7 pg, and the copper element as 0.42 pg with 1000 nm Si3N4 coated wafers.
  • Master Thesis
    Temperature Dependence of Zero Phonon Line Emission From Defects in Hexagonal Boron Nitride and Design of Photon-Pair Source
    (Izmir Institute of Technology, 2017) Polat, Nahit; Ateş, Serkan
    This thesis presents studies of the defect centers in hBN and design of nonlinear waveguide. The multilayer hBN flakes and Si3N4 waveguide are available materials in modern nanophotonics applications. The color centers in hBN are consisted of quantized states because each defect center has different saturation power and dipole polarization. The line shape of emission from defect centers is directly depended photon vibrations and temperature of sample. Moreover, phonon bands in the color centers affect the wavelength of emission and we statistically worked on the phonon effects on ZPL. The Si3N4 waveguide can be more efficient chip scale photon pair sources to create entangled photons in visible band. The zero dispersion wavelength calculations give an efficient waveguide geometry as 650×600 nm2 for 780 nm pump wavelength.