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Öğe Amplifying main physical characteristics of CuO films using ascorbic acid as the reducer and stabilizer agent(Springer Heidelberg, 2021) Akkaya, Abdullah; Kahveci, Osman; Aydin, Rasit; Sahin, BunyaminCopper oxide thin films have been grown by successive ionic layer adsorption and reaction technique, which is inexpensive, environmentally friendly and simple onto soda-lime glass substrates from an aqueous copper (II) chloride dehydrate solution with and without the addition of ascorbic acid (AA) at 70 degrees C. Surface morphology, crystalline structure, chemical compositions, optical and electrical properties of thin films were investigated with a focus on the influences of different concentrations of AA. The analysis exhibited that the main physical performances of the CuO films were found to change with AA content. Estimated crystallite sizes decreased from 24.64 to 12.78 nm with the addition of AA in the growth bath solutions. The optical bandgap energy of CuO is found to increase from 1.42 to 1.55 eV as a consequence of the increasing AA content. As the AA concentration in the solution bath increases the transmittance increases from approximate to 5 to approximate to 28%. FTIR transmittance spectra of CuO have a characteristic stretching vibration mode of the metal-oxide bonds and the addition of AA caused the appearance of many peaks of this molecule. Contact resistance values decreased with the AA content from 0.657 x 10(9) to 0.342 x 10(9) omega. It is worth noting that the deposition technique is low cost and very simple; obtained CuO thin films could be appropriate for different technological applications.Öğe Green and cost-effective synthesis of zinc oxide thin films by L-ascorbic acid (AA) and their potential for electronics and antibacterial applications(Elsevier Sci Ltd, 2022) Tasdemir, Abdulkadir; Akman, Nazife; Akkaya, Abdullah; Aydin, Rasit; Sahin, BunyaminThe evolution of eco-friendly, green route and cheap technology for synthesizing nanostructured zinc oxide (ZnO) thin films using plant extracts is a promising choice because such materials present a widespread potential for numerous technological applications. This study proposes the green and cost-effective technique to synthesize stable ZnO thin films using a good reducing agent and facilitating many natural L-ascorbic acids (AA) metabolic reactions capacity. The influence of AA concentrations in the starting bath solution on ZnO samples' structural, morphological, electrical and antibacterial performances has been reported in detail. The main physical char-acteristics of the ZnO materials were improved by supplementing of reducing and capping agents AA. Average particle size varies with the adding AA from 58.29 to 48.68 nm and also thickness of these films was decreased from 0.82 to 0.44 mu m. Also, it was seen that, the presence of AA in the bath solution significantly affected the absorption process and causes a morphological alteration due to the reaction between Zn2+ and AA during the deposition process. FTIR transmittance spectra of bare ZnO presented that a transmittance peak about 886 cm(-1) and 748 cm(-1) was created by the characteristic stretching vibration mode of the Zn-O. The resistivity of the produced films significantly changed with AA concentration in the bath solution. Antibacterial potentials of bare ZnO and ascorbic acid added ZnO films were examined against economically important Staphylococcus aureus (ATCC 25923) gram-positive bacteria and Escherichia coli (ATCC 35218) gram-negative bacterial disease agents via handling paper disc diffusion assay. The obtained diameter of the zones of inhibition was 20.1 mm for E. coli and 28.1 mm for S. aureus at the dose of ZnO+AA 8.0%. These inhibition diameters were larger than the diameter of ampicillin as our positive control alone. This proves that the newly synthesized compound is a powerful antibacterial agent.Öğe Growth and characterization of Fe-doped CuO/ZnO binary oxide thin films for possible optoelectronic applications(Elsevier, 2024) Sogan, Serra; Yucel, Ersin; Sarikaya, Ebru Karakas; Kahveci, Osman; Aydin, Rasit; Akkaya, Abdullah; Sahin, BuenyaminNanoscale binary oxide thin film structures of pristine and Fe-substituted CuO/ZnO have been produced on sodalime glass substrates by the SILAR method and characterized by different acceptable analytical approaches. The more irregular and lumpy ZnO in the pristine CuO/ZnO binary thin film sample evolved into more regular and hexagonal prismatic structures with the addition of Fe. XRD patterns of the samples indicated that both monoclinic CuO and hexagonal ZnO phases were present without any impurities. Optical analyses by meaning absorbance and transmittance measurements exhibit an important change in the energy band gap and transmittance value with the Fe doping ratio. The energy band edges of the bare sample shift to red with increasing Fe percentage in the starting solution, presumably due to an increase in the carrier concentration. The transfer length method (TLM) is used to define the conductivity properties of the samples, which considers the contact properties and structural features of thin films. The minimum specific contact resistivity of 0.865 x 10 6 Omega square was obtained by 3.0 % Fe-implemented CuO/ZnO binary oxide samples, and the addition of Fe increased the effective transfer length of thin films.Öğe Investigation of Multi-Phase Structure and Optoelectronic Performance of Bi-Doped (Cu-Zn) Oxide Composite Thin Films(Wiley-V C H Verlag Gmbh, 2023) Altinay, Yasemin; Akkaya, Abdullah; Aydin, Rasit; Sahin, BunyaminIn this research, thin film composite structures were used to prepare optoelectronic devices from bare and Bi-substituted p-CuO/n-ZnO systems. The p-CuO/n-ZnO composite thin film structures were prepared by the SILAR technique, and the influences of two different Bi contents on the structure and main physical performances of the samples were investigated. The X-ray diffraction (XRD) technique showed that the composited thin film materials were multiphased in rutile hexagonal (wurtzite) phase (ZnO) and monoclinic tenorite phase (CuO) type crystal structure. The obtained surface morphological results presented that the structure exhibits an almost homogeneous, plate-like surface distribution, and depending on the increase of Bi concentration, the plate-like sheet area widens from similar to 2.5 mu m to 10 mu m and the layer boundaries decrease. FT-IR and Raman spectroscopy were used to investigate the various vibration and Raman active phonon modes of Bi:p-CuO/n-ZnO nanostructured heterostructures. For a comprehensive analysis of the optical bandgap of the fabricated composite samples, the estimated values were obtained from the Tauc plot. Produced samples exhibited an Ohmic behavior and dc resistivity values of films can be determined via Ohm's Law. The adjusted sheet resistance value of 11.51 M Omega/sq when the content of Bi 3.0 % in the growth bath.
