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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 Comprehensive research on physical properties of Zn and M (M: Li, Na, K) double doped cadmium oxide (CdO) nanostructures using SILAR method(Elsevier Sci Ltd, 2017) Aydin, Rasit; Sahin, BunyaminThis research outlines the effect of Zn doping, (Zn+Li), (Zn+Na) and (Zn+K) doubly doping of nanostructured CdO films on the structural, morphological and optical properties of the films. Un-doped, Zn-doped, (Zn+Li), (Zn+Na) and (Zn+K) double doped CdO films were synthesized on soda lime glass substrates by the SILAR method. Manufactured CdO films attached well to the glass substrates, exhibited nano-sized structures, and the physical properties of the nanoparticles were modified by co-doping. The XRD analysis confirmed that all the films exhibited face-centered cubic structure with (111) and (200) preferential growth. Calculated crystallite size values of the CdO films via the Scherrer equation decreased with Zn doping and double-doping. Optical measurements revealed that doping modifies the band gap enabling the potential of these films to be utilized in optoelectronic applications.Öğe Double doping synergy to improve structural, morphological, optical, and electrical properties of solution-based Cd and M (M: Pb, Sn, Bi) double doped nanocrystalline copper oxide films(Springer Heidelberg, 2019) Sahin, Bunyamin; Aydin, RasitIn this study, nanostructured CuO, Cd0.01Cu0.99O and Cu0.98Cd0.01M0.01O (M: Pb, Bi, Sn) films were synthesized using the successive ionic layer adsorption and reaction technique. The effects of Cd-doping, Sn, Pb, and Bi double doping on the structural, morphological, optical, and electrical properties were systematically investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, and current-voltage (I-V) measurements, respectively. XRD results show that the peak intensity, crystallite size, and texture coefficient of the films changed intensely with double doping. SEM images reveal that the surface morphology of the nanostructures changed with the kind of dopant materials due to the differences in ionic radius. Energy dispersive X-ray spectroscopy studies confirmed the presence of Cd2+, Sn4+, Pb2+, and Bi+5 in the doped films. The estimated average optical band gap energies of the CuO samples varied from 1.366 to 1.480 eV with double doping. The lowest average electrical resistivity of 1.21 x 10(6) ohm cm was found for the Bi-0.01 Cd0.01Cu0.98O sample.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.Öğe The role of Triton X-100 as a surfactant on the CdO nanostructures grown by the SILAR method(Elsevier Science Sa, 2017) Aydin, Rasit; Sahin, BunyaminIn this work, the effect of surfactant Triton X-100 (TX-100) on structural, morphological and optical properties of nanostructured CdO films has been researched. Four series of nanostructured CdO films with TX-100 concentrations of 0.25e1.0 M% of the growth solution were prepared by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique on glass substrates and were characterized by scanning electron microscopy, surface roughness, X-Ray diffraction and UV-Vis. Spectroscopy. Scanning electron microscopy exhibited that the particle thickness increased with increasing TX-100 content. Surface roughness (Ra) measurement exhibited that Ra value accordingly decreases in the presence of TX-100. From the X-Ray diffraction patterns it was calculated that the crystallite size of the films increased parallel to the particle size with increasing TX-100 content. UV results presented that the optical bandgap values of the film can be adjusted with TX-100 content where optical bandgap decreased with increasing TX-100 content in the growth bath. The results show that the amount of TX-100 in the growth bath played a significant mission in adjusting the main physical properties of the nanostructured CdO film. (C) 2017 Elsevier B. V. All rights reserved.Öğe Sodium dodecyl sulfate-assisted SILAR synthesis of nanostructured cadmium oxide films(Elsevier Sci Ltd, 2016) Aydin, Rasit; Sahin, Bunyamin; Bayansal, FatihNanostructured CdO films were prepared on glass substrates by a surfactant sodium dodecyl sulfate (SDS) assisted SILAR technique. The influence of SDS concentrations of the growth solution on the structural, morphological and optical properties of the films was investigated and discussed. From the metallurgical microscope and scanning electron microscope images, it was seen that the surface morphology of the films are significantly enhanced by SDS addition. XRD investigations confirmed that the films have good crystallinity levels and are grown preferentially in (111) and (200) orientations. UV-vis. spectroscopy investigations showed that the bandgap and transmittance values of the films are affected dramatically by SDS concentrations. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Öğe A study of the influences of transition metal (Mn,Ni) co-doping on the morphological, structural and optical properties of nanostructured CdO films(Springer, 2018) Gurbuz, Elif; Aydin, Rasit; Sahin, BunyaminIn this paper, a systematic investigations on the effects of transition metals such as Mn and Ni-dopant on physical properties of cadmium oxide (CdO) thin films coated on soda lime glass substrates by using SILAR method have been reported. The characterizations of un-doped, Mn-doped (Cd-0.99 Mn0.01O) and Mn/Ni double doped CdO [(Cd0.99-xMn0.01NixO)(0 <= x <= 0.001)] films were investigated by SEM, EDX, XRD and UV-Vis spectrophotometry to determine the morphological, structural and optical properties, respectively. SEM analysis showed that the surface morphologies of the CdO films were influenced by Mn doping and Mn/Ni co-doping. The EDX result verified the presence of expected elements Cd, O, Mn and Ni in the growing solution. The crystal phases of the samples and their crystallinity quality have been investigated by XRD measurements. The X-ray diffractograms show all the diffraction peaks are highly intense also they demonstrate the preferential orientations of (111) and (200) directions. Optical investigations revealed red shift with Mn doping and Mn/Ni co-doping in the absorbance spectrum.Öğe Syntheses, structural evolution, electrical and optoelectronic characterization of ZnO/CuO composite films doped with transition metal Mn2+ ions(Elsevier Sci Ltd, 2022) Safdar, Hamza; Aydin, Rasit; Sahin, BuenyaminThis study was done aiming to evaluate the influence of manganese (Mn) as a transition metal on the morphological, structural, optical, electrical, and optoelectronic characteristics of nanostructured ZnO/CuO films. Different Mn concentrations (1 and 2 M%) were used to analyze these properties. In the present research, we have described the synthesis of nanocomposite pristine ZnO/CuO and Mn-doped ZnO/CuO (Mn: ZnO/CuO) oxide films by using simple successive ionic layer adsorption and reaction (SILAR) procedure. Scanning electron microscopy (SEM) and atomic force microscope (AFM) pictures reveal that the surface structure of ZnO/CuO nanocomposites was effectively altered by Mn2+ ion substitution. Energy-dispersive X-ray analysis (EDX) con-firms the presence of Zn, Cu, O, and Mn elements in the synthesized nanofilms. The film thickness had decreased from 1.65 to 1.23 mu m as a function of increasing Mn2+ concentration. The X-ray diffraction (XRD) pattern revealed that the synthesized ZnO/CuO nanocomposite was polycrystalline and the crystallite size decreases from 40.16 to 34.14 nm with increasing Mn2+ ion concentrations. The optical bandgap energy was found using Tauc's graph and it varied from 2.37 to 2.56 eV. A maximum average transmittance (30%) was obtained for 2 M % Mn2+ concentration. Electrical measurement of the ZnO/CuO composite films shows sheet resistance (Rs) change between 1.01 and 0.41 (x108 omega/sq.) depending on temperature from 300 K to 400 K. The biggest figure of merit observed in this work was 4.69 x 10-8 omega- 1. The results have shown that Mn-doping has an important effect on the physical attributes of SILAR-deposited ZnO/CuO films.Öğe Tuning the morphological, structural, optical and dielectric properties of hausmannite (Mn3O4) films by doping heavy metal lead(Academic Press Ltd- Elsevier Science Ltd, 2020) Sahin, Bunyamin; Aydin, Rasit; Cetin, HidayetIn this study, we reported a systematic approach to prepare bare and lead doped Mn3O4 films synthesized by the SILAR method. Morphological, structural, optical and dielectric specialties of the Mn3O4 films were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Energy Dispersive Spectrometry (EDS), X-ray diffraction (XRD) analysis, Ultra-violet-Visible (UV-Vis) spectrophotometry and the impedance analysis, respectively with respect to changes in Pb dopant quantity. SEM and AFM analysis exhibited that Pb-doping influenced the morphology of the film surface. X-ray diffraction patterns proved that films have a cubic crystal structure with preferential orientations of (104) and (211) planes. The crystallite sizes of the bare and lead-doped Mn3O4 films were found to vary from 20.80 to 10.20 nm. The bandgap value of the Mn3O4 films increases from 2.20 eV to 2.38 eV after doping Pb. The dielectric constant, AC conductivity, and loss tangent of the produced samples were studied in the frequency range of 20 Hz-1 MHz. The analysis results showed that the dielectric constant and AC conductivity of the Mn3O4 compound had changed drastically with the doping of Pb. The dielectric constant and AC conductivity rose from 1703 to 120777 and from 3.35 x 10(-5) to 2.6310(-3) S/m at 100 Hz with 0.25 M% Pb-doping, respectively.
