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Öğe Improvement of structural, optical and magnetic properties of cobalt oxide thin films by doping with iron(Springer Science and Business Media Deutschland GmbH, 2021) Küçükarslan, Ayşe; Kuş, Esra; Sarıca, Emrah; Akyüz, İdris; Bilgin, Vildan; Demirselçuk, BarbarosIn this study, using the ultrasonic spray pyrolysis technique, undoped and Fe-doped (at 2, 4, 6%) Co3O4 films were deposited on microscope glass substrates at 300 ± 5 °C, and the effect of Fe doping on some physical properties of Co3O4 films was examined. The structural, optical, magnetic and morphological properties of all films were analyzed using X-ray diffractometer, UV–Vis spectrophotometer, vibrating sample magnetometer and atomic force microscope, respectively. Band gap values of Co3O4:Fe films were found to be between 1.98 and 2.12 eV with an additional sub-band corresponding to energies varying between 1.48 and 1.50 eV for all samples. Structural analysis showed that crystallization levels of the films were improved with the Fe doping. Also, hysteresis curves of the films showed weak ferromagnetic characteristics and the magnetic behavior of the films was found to be sensitive to doping amount of Fe. It was found that Fe doping has beneficial effect on some physical properties of Co3O4 films.Öğe Optimization of chemically sprayed ZnS films by Mn doping(Elsevier, 2021) Demirselçuk, Barbaros; Kuş, Esra; Küçükarslan, Ayşe; Sarıca, Emrah; Akyüz, İdris; Bilgin, VildanIn this study, undoped and Mn doped ZnS films were grown on microscope glass substrates at substrate tem- perature of 400 ± 5 ◦C by using a low cost Ultrasonic Spray Pyrolysis technique, and the effect of Mn doping on some physical properties of ZnS films was investigated. Structural, optical, electrical and morphological prop- erties of all films were analyzed using X-ray diffractometer (XRD), UV–Vis spectrophotometer, two-probe technique and atomic force microscope (AFM), respectively. X-ray diffraction studies showed that all films were formed in ZnS hexagonal structure and the crystallization levels of the films were relatively improved due to the increase in the Mn doping ratio, especially for 4% doped films. It was determined that the average transmittance value of undoped ZnS film in the visible region is 38% and this value increases to 60% for the sample doped by Mn at the highest rate (12%). The band gap values of the films were calculated using the Tauc equation and determined to be between 3.82 and 3.94 eV. Electrical resistivity values of the films decreased significantly due to the Mn doping. Mn doping also caused ZnS films to have uniform surface morphologies consisting of noticeable particle formations. Figure of merit calculations showed that Mn doping has a favorable effect on ZnS films and ZnS:Mn (12%) films may be promising materials for applications such as photovoltaic solar cells and optoelectronic devices.Öğe Ultrasonically sprayed cobalt oxide thin films: Enhancing of some physical properties by nickel doping(Elsevier B.V., 2021) Kuş, Esra; Küçükkarslan, Ayşe; Demirselçuk, Barbaros; Sarıca, Emrah; Akyüz, İdris; Bilgin, VildanIn this study, the effect of Ni doping (3, 6, 9 at%) on structural, optical, electrical and magnetic properties of Co3O4 films was reported. Films were grown at 300 ± 5 °C substrate temperature via ultrasonic spray pyrolysis (USP) technique. The structural analyses showed that undoped and Ni (3%) doped films exhibit an amorphous structure. Ni doping at higher ratios caused the films to have improved crystallinity. Optical band gap values the films were found to be between 2.03 and 2.08 eV with an additional sub-band corresponding to energies varying between 1.35 and 1.46 eV. The electrical conductivity values of the films increased significantly depending on the Ni doping. The hysteresis curves of the films showed that the films have weak ferromagnetic properties. Ni doping significantly improved the structural and electrical properties of Co3O4 films making them suitable materials for technological applications.Öğe Ultrasonik spray pyrolysis ile büyütülen ZnS ince filmlerinin fiziksel özellikleri üzerine fe katkısının etkisi(Çanakkale Onsekiz Mart Üniversitesi, 2019) Kuş, Esra; Özder, SerhatBu tez kapsamında, II-VI grubu bileşiklerinden olan ZnS ince filmleri, opto-elektronik alanında, oda sıcaklığında 3,5-3,7 eV gibi geniş band aralığına sahip olmasından dolayı görünür bölgede ışık yayan diyot olarak kullanılmakta ve çeşitli elektronik cihazların tasarımında da umut verici bir malzemedir. Son yıllarda ZnS yarıiletken filmlere geçiş elementlerinin katkılanması sonucunda spintronik ve opto-elektronik teknolojisinde önemli gelişmelerin sağlanmasında katkısı bulunmaktadır. Bu çalışmada katkısız ve farklı oranlarda geçiş elementleri katkılı ZnS ince filmler Ultrasonik Spray Pyrolysis tekniği ile mikroskop cam tabanlar üzerine üretilecektir. ZnS filmlerine manyetik özellik kazandırmak amacıyla Fe ve Ni gibi geçiş elementleri katkı elementi olarak tercih edilecektir. Üretilen filmlerin bazı fiziksel özellikleri incelenerek, geçiş elementlerinin ZnS ince filmlerinin fiziksel özellikleri üzerindeki etkisi araştırılacaktır. ZnS filmlerinin optiksel, elektriksel, magnetik, yapısal ve yüzeysel özellikleri sırasıyla UV-Vis spektrofotometre, dört-uç metodu, titreşen örnek magnetometresi (VSM), x-ışını difraktometresi (XRD) ve atomik kuvvet mikroskobu (AFM) ile incelenecektir. Tüm elde edilen analiz sonuçlarından, katkılı ve katkısız ZnS filmlerinin spintronik devrelerde, opto-elektronik endüstrisinde ve fotovoltaik güneş pillerinde uygulama potansiyelleri araştırılacaktır.
