Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 4Photocatalytic and Optical Properties of Zinc Oxide Structures Prepared at Different Urea Concentrations(Serban Solacolu Foundation, 2020) Uysal, Berk; Şen, Selin; Top, AybenIn this study, ZnO samples were synthesized using zinc acetate and urea with a method containing sonication, sol-gel transition and calcination steps. Urea to zinc acetate mole ratio values were changed as 0, 0.5, 1, and 2 and corresponding calcined samples were denoted as UZ-0, UZ-0.5, UZ-1, and UZ-2, respectively. Scanning electron microscopy (SEM) images indicated globular and rod-like structures. Aspect ratios of the nanorods increased as urea to zinc acetate ratio increased from 0 to 1 whereas nanoparticles with sizes of 70 +/- 20 nm were observed for UZ-2 sample. Brunauer, Emmett and Teller (BET) surface area values of the samples varied between 9 and 25 m(2)/g and increased as initial urea amount increased. Band gap energies of the samples ranged between 3.24 and 3.29 eV. Four major peaks at about 400, 420, 480 and 530 nm with different intensities were observed in the photoluminescence (PL) spectra of the samples. All the samples removed rhodamine B by both adsorption and photodegradation. The highest visible light induced photodegradation rate was exhibited by UZ-2 sample having the highest surface area and it is attributed to superior charge separation properties of this sample under visible light.Article Citation - WoS: 1Citation - Scopus: 2Electron Field Emission From Sic Nanopillars Produced by Using Nanosphere Lithography(AVS Science and Technology Society, 2017) Yeşilpınar, Damla; Çelebi, CemField emitter arrays of silicon carbide based nanopillars with high emitter density were fabricated by using a combination of nanosphere lithography and inductively coupled plasma reactive ion etching techniques. The electron field emission characteristics of the produced nanopillars with two different aspect ratios and geometries were investigated, and the obtained results were compared with each other. The authors found that unlike the samples containing low aspect ratio SiC nanopillars with blunt tip apex, the samples comprising high aspect ratio nanopillars with sharp tip apex generate greater emission currents under lower electric fields. The nanopillars with sharp tip apex produced field emission currents up to 240 μA/cm2 under 17.4 V/μm applied electric field, while the nanopillars with blunt tip apex produced an emission current of 70 μA/cm2. The electric fields required to obtain 10 μA/cm2 current density are found to be 9.1 and 7.2 V/μm for the nanopillars with blunt and sharp tip apex, respectively. Time dependent stability measurements yielded stable electron emission without any abrupt change in the respective current levels of both samples.