Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Citation - WoS: 12Citation - Scopus: 11Theoretical and Experimental Investigation of Conjugation of 1,6-Hexanedithiol on Mos2(IOP Publishing Ltd., 2018) Gül, Aytaç; Bacaksız, Cihan; Ünsal, Emre; Akbalı, Barış; Tomak, Aysel; Zareie, Hadi M.; Şahin, HasanWe report an experimental and theoretical investigation of conjugation of 1,6-Hexaneditihiol (HDT) on MoS2 which is prepared by mixing MoS2 structure and HDT molecules in proper solvent. Raman spectra and the calculated phonon bands reveal that the HDT molecules bind covalently to MoS2. Surface morphology of MoS2/HDT structure is changed upon conjugation of HDT on MoS2 and characterized by using Scanning Electron Microscope (SEM). Density Functional Theory (DFT) based calculations show that HOMO-LUMO band gap of HDT is altered after the conjugation and two-S binding (handle-like) configuration is energetically most favorable among three different structures. This study displays that the facile thiol functionalization process of MoS2 is promising strategy for obtaining solution processable MoS2.Article Citation - WoS: 2Citation - Scopus: 2The Effect of Thickness of Silver Thin Film on Structural and Optical Properties of Porous Silicon(World Scientific Publishing Co. Pte Ltd, 2017) Çetinel, A.; Özdoğan, M.; Utlu, G.; Artunç, N.; Şahin, G.; Tarhan, EnverIn this study, porous silicon (PS) samples were prepared on n-type silicon (100) wafers by electrochemical etching method, varying the current density from 20 to 100mA/cm2 and keeping constant HF concentration (10%) and etching time of 15min. Then, Ag thin films, which have 10, 50 and 100nm film thicknesses, were deposited on PS layers by using thermal evaporation to investigate the influence of Ag film thickness on structural and optical properties of PS. The structural and optical properties of PS and Ag deposited PS layers have been investigated by XRD, FE-SEM, Raman and photoluminescence (PL) spectroscopy. FE-SEM XRD and Raman analyzes indicate that average pore size and porosity of PS layers increase with the increasing current density. Further, Ag nanoparticles have embedded in pore channel. PL measurement reveals that higher porosity of PS would be better to form the Ag-PS nano-composite material leading to stronger PL band. The PL spectra of PS and Ag-PS samples indicate that PL bands show blue shift with increasing current density and film thickness. Consequently, it has been found that the structural and optical properties of PS depend on current density and Ag film thickness individually.Article Citation - WoS: 12Citation - Scopus: 12Ge Nanocrystals Embedded in Sio2 in Mos Based Radiation Sensors(Elsevier Ltd., 2010) Aktağ, Aliekber; Yılmaz, Ercan; Mogaddam, Nader A.P.; Aygün, Gülnur; Cantaş, Ayten; Turan, RaşitIn this work, the effects of gamma radiation on the Raman spectra of Ge nanocrystals embedded in SiO2 have been investigated. SiO2 films containing nanoparticles of Ge were grown using the r.f.-magnetron sputtering technique. Formation of Ge nanocrystals was observed after high temperature annealing in an inert atmosphere and confirmed by Raman measurements. The intensity of the Raman signal originating from Ge nanocrystals was found to decrease with increasing gamma radiation. The study also includes the gamma radiation effects on MOS structure with Ge nanocrystals embedded in SiO2. The gamma radiation effects from 500 up to 4000 Gray were investigated. Capacitance-voltage measurements were performed and analyzed. Oxide traps and interface trap charges were calculated. Results show that MOS structure with Ge nanocrystals embedded in SiO2 is a good candidate to be used in radiation sensors, especially at high radiation doses. © 2010 Elsevier B.V. All rights reserved.