Optical characterization of silicon based hydrogenated amorphous thin films by un-visible and infrared measurements

Kılıç, İlker
Various carbon content hydrogenated amorphous silicon carbide (a-Si1ŁxCx:H) and hydrogenated amorphous silicon (a-Si:H) thin films have been deposited on various substrates by using plasma enhanced chemical vapour deposition (PECVD) technique. Transmission spectra of these films have been determined within UV-Visible region and the obtained data were analysed to find related physical constants such as; refractive indices, thicknesses, etc. Fourier transform infrared (FT-IR) spectrometry technique has been used to determine transmission & reflection type spectra of these films. Obtained data were analysed to determine bond structures of the films. E®ects of relative concentration of ethylene (C2H4) gas on thin film bond structure and on optical constants have been questioned


Surface-enhanced Raman scattering spectroscopy via gold nanostars
Nalbant Esentürk, Emren (Wiley, 2009-01-01)
Anisotropic metallic nanoparticles (NPs) have unique optical properties, which lend them to applications such as surface-enhanced Raman scattering (SERS) spectroscopy. Star-shaped gold (Au) NPs were prepared in aqueous solutions by the seed-mediated growth method and tested for Raman enhancement using 2-mercaptopyridine (2-MPy) and crystal violet (CV) probing molecules. For both molecules, the SERS activity of the nanostars was notably stronger than that of the spherical Au NPs of similar size. The Raman en...
Terahertz Transmission Through Patterened Vanadium Oxide Thin Films on Dielectric Substrates
AKKAYA, MAHİNUR; Demirhan, Y.; Yuce, H.; Aygun, G.; Ozyuzer, L.; SABAH, CUMALİ; Altan, Hakan (SCITEPRESS, AV D MANUELL, 27A 2 ESQ, SETUBAL, 2910-595, PORTUGAL; 2017-03-01)
Patterned and unpatterned films of vanadium oxide grown on dielectric substrates such as fused silica and sapphire were grown and analysed by varying the temperature using terahertz time domain spectroscopy. After investigating the critical transition temperature near 340K, a well-known cross-shaped pattern was studied to observe any resonances upon transmission. Due to the poor conductivity of the films the frequency selective nature of the structure was not observed, however an etalon effect could be seen...
Optimization of microwave-assisted extraction of phenolic compounds from tomato: Characterization by FTIR and HPLC and comparison with conventional solvent extraction
Baltacıoğlu, Hande; Baltacıoğlu, Cem; Okur, İlhami; Tanrıvermiş, Arif; Yalıç, Muharrem (Elsevier BV, 2021-03-01)
© 2021 Elsevier B.V.In the extraction of phenolic compounds from tomato, Microwave-Assisted Extraction (MAE) was used as a novel technology in this study and compared to conventional solvent extraction (CSE). The optimal extraction conditions for tomato were determined using the multi-level factorial design. For this purpose, different powers (360, 600 and 900 W) and times (30, 60 and 90 s) were used for MAE and also different temperatures (40, 50 and 60 °C) and times (10, 20 and 30 min) were used for CSE. ...
ERGUCYENER, C; AYGUN, S; Ataman, Osman Yavuz; TEMIZER, A (1988-01-01)
Mercury speciation in aqueous solutions containing inorganic mercury and methylmercury has been demonstrated using electrochemical separation prior to determination by cold-vapour atomic absorption spectrometry. Approximately 95% of the inorganic mercury was electro-deposited on a Pt electrode at –0.1 V, whereas for methylmercury –0.2 V or even more negative potentials were required. Organic mercury was determined by NaBH4 reduction after electrochemical separation. Inorganic mercury was determined in the o...
Exciton simulations of the optical properties of several photosynthetic light-harvesting complexes
İşeri, Erkut İnan; Gülen, Demet; Department of Physics (2004)
The work presented in this thesis was aimed to investigate the structure-function relationship of several photosynthetic Light-Harvesting Complexes (LHCs) including Chlorophyll Protein 29 (CP29) and Light-Harvesting Complex II (LHCII) of green plants, and Fenna-Matthews-Olson (FMO) complex of green sulfur bacterium Chlorobium tepidum. Based on the exciton calculations, a model was proposed to the electronic excited states (EES) of both CP29 and LHCII complexes by incorporating a considerable part of the cur...
Citation Formats
İ. Kılıç, “Optical characterization of silicon based hydrogenated amorphous thin films by un-visible and infrared measurements,” M.S. - Master of Science, Middle East Technical University, 2006.