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    Öğe
    Annealing time effect on the optical properties of Zn(O,OH,S) films onto ZnO seed layer under un-vacuum ambient
    (2018) Özütok, Fatma; Yakar, Emin
    In this study, Zn (O,OH,S) films were synthesized onto ZnO seed layers by chemical bath deposition, which wereannealed at 500 °C. The differences of structural, morphological and detailed optical properties of the films wereinvestigated depending on the annealing time (between 30 min. and 90 min.). While samples of 30.min and 90 min.showed decomposed structures, sample of 60 min. showed different dimensions of nano-flower structures. Althoughall films had ZnO-hexzagonal crystal structure, the most obvious ZnS-related peaks were observed in the sample of90 min. Optical absorption edge was shifted at 362 nm from Uv-Vis spectroscopy. Although ZnO, Zn(OH)2 vibrationrelated peaks were so sharp, ZnS vibration peaks were so weak for all samples from FTIR. The PL intensities weredifferential depending on the annealing time but defect state-corresponding peaks were similar for each films.
  • Küçük Resim
    Öğe
    Enhancing the Co gas sensing properties of ZnO thin films with the decoration of MWCNTs
    (Springer, 2019) Özütok, Fatma; Karaduman Er, Irmak; Acar, S.; Demiri, S.
    Multi-walled carbon nanotubes (MWCNTs) onto flower-like patterned ZnO seed layers were prepared by spin coating method. The etching of the MWCNTs was examined by HCl acid treatment. The effect of structural, morphological and elemental properties of the ZnO/MWCNTs were determined by XRD, SEM, and EDX, respectively. The gas sensing properties of ZnO seed layer and MWCNT/ZnO nanocomposites were studied as a function of operating temperature and gas concentration. The incorporation of MWCNT were given results such as reducing the operating temperature to 70 degrees C and enhancement in sensor response for 25ppm CO gas. It was obtained that the highest sensing response of 62% at 70 degrees C for raw-MWCNTs/ZnO sensor as compared to etched-MWCNT/ZnO and ZnO sensor which gave a sensing response of 19% and 21% at operating temperature of 70 degrees C and 150 degrees C, respectively. Results showed that the deposition of metal oxide sensors with MWCNT is a promising strategy for improvement of CO gas sensing properties.
  • Küçük Resim
    Öğe
    Sensör uygulamaları için metal oksit ince filmlere metal ve/veya karbon nanotüp modifikasyonu ile nanokompozitlerin eldesi
    (Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2016) Özütok, Fatma; Demiri, Sani
    Bu tez çalışmasında kimyasal banyolama tekniği ile ZnO ve Al:ZnO ince filmleri ve spin kaplama tekniği ile ZnO/ÇDKNT nanokompozitleri sentezlenmiştir. ZnO ince filmleri üzerine tavlamanın, Al:ZnO filmleri üzerine farklı Al-kaynak çözeltisinin ve ZnO/ÇDKNT nanokompozitleri üzerine ÇDKNT'lerin asit oksidasyonu ile saflaştırma prosesinin etkileri araştırılmıştır. Sentezlenen malzemelerin farklı parametreler altında uygun karakterizasyon teknikleri kullanılarak (XRD, SEM, EDX ve Uv-Vis spektroskopisi) bu yapıların yapısal, optiksel ve elementel özellikleri incelenmiştir. Ayrıca, bu parametreler etkisi altında bahsi geçen malzemelerin farklı gazlara karşı duyarlılıkları araştırılarak çıkan sonuçlar detaylı bir şekilde incelenmiştir. ZnO ince filmleri için NO2, Al:ZnO ince filmleri ve ZnO/ÇDKNT nanokompozitleri için NH3 gaz duyarlılıkları ölçülmüştür.