Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Characterization of Ion Implanted Surfaces by Laser Induced Breakdown Spectroscopy, Libs(01. Izmir Institute of Technology, 2008) Örer, Sabiha; Yalçın, ŞerifeLaser Induced Breakdown Spectroscopy, LIBS, is a versatile atomic emission spectrometric technique for the determination of the elemental composition of solids, liquids, gases and aerosols with the need for little or no sample preparation.In this study, an optical LIBS system from its conventional parts was designed, constructed and optimized for spectrochemical analysis of solid materials. Specifically, the 2-D elemental distribution of Ge ions on silicon oxide surfaces, prepared by the method of ion implantation, with differing atomic concentrations between 1016 - 1017 ions/cm2 have been investigated by LIBS. For this purpose a Nd: YAG laser operating at the second harmonic wavelength, 532 nm, was used to create a plasma on the material surfaces. Spatially and temporally resolved atomic emission from the luminous plasma was detected by an Echelle spectroctrograph and Intensified Charged Coupled Device (ICCD) detector combination. Spectral emission intensity from the LIBS measurements has been optimized with respect to time, crater size, ablation depth and laser energy. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-Ray Spectroscopy (EDX) have been utilized to obtain crater depth, morphology and elemental composition of the sample material, respectively. LIBS spectral data revealed the possibility of performing 2-D distribution analysis of Ge ions over the silicon oxide substrate at Ge ion concentrations lower than 0.5% (atomic). LIBS as a fast semi-quantitative analysis method with 50.m lateral and 800 nm depth resolutions has been evaluated. In this wok, elemental analysis of some metal surfaces, such as Al and Cu, was also performed by LIBS.Keywords: LIBS, surface analysis, Ge ion implantation, lateral resolution,Master Thesis Determining Charge Distribution of Metal Oxide Surfaces With Afm Using Colloid Probe Technique(Izmir Institute of Technology, 2012) Güler, Ayşe; Polat, MehmetColloidal systems of micron-sized particles dispersed in a solvent are widely encountered in numerous industries. Homogeneity, dispersibility, rheology and forming characteristics of these systems depend solely on particles-particle interactions which in turn are determined by Van der Waals (vdW) and Electrical Double Layer (EDL) forces. The vdW forces are not affected by system chemistry. However, the EDL forces, which arise from the charging of on solid surfaces in a solvent, vary significantly with solution chemistry. So, manipulation of electrical forces is used widely in industrial applications to manipulate colloidal systems. Colloidal particles in solution carry a distribution of positive, negative and neutral charges depending on solution chemistry. Electrophoretic potential mesurements or colloidal titration methods yield only an average charge for the whole population, not the charge distribution on each particle surface. The streaming potential techniques also provide an average charge on the surface. Currently, there is no accepted technique to determine the charge distribution on solid surfaces. This work aims at using Atomic Force Microscopy (AFM) as a charge probe to achieve exactly this. The work improves on a recent study (Yelken, 2010) which used commercial SiN4 cantilevers to determine the charge distribution on quartz and sapphire surfaces by replacing SiN4 cantilevers with custom-made colloid probes of desired material (quartz in this case) to probe the surface. The current work which improves the flexibility and resolution of the method was tested with two quartz and