Papers by Vagif Nevruzoglu
Energy Sources, Part A: Recovery, Utilization, And Environmental Effects, Jun 24, 2020
In this study, ZnO thin films were grown on glass, n-Si (100), c axis textured graphite and indiu... more In this study, ZnO thin films were grown on glass, n-Si (100), c axis textured graphite and indium tin oxide coated glass (ITO) substrates by ultrasonic spray pyrolysis method. X-ray diffraction studies showed that ZnO samples have hexagonal structure with (002) preferred direction. The preferred orientation of the sample prepared on ITO substrate changed from (002) to (101). Some diffraction peaks of graphite and ITO substrates were observed in X-ray diffraction pattern. Lattice parameters of ZnO samples grew on glass, graphite and ITO substrates were approximately equal to lattice parameters of bulk ZnO ( a = 3.249 A and c = 5.206 A). Quasi-aligned hexagonal shaped ZnO microrods were obtained for glass and ITO substrates. Room temperature photoluminescence measurements indicated a sharp ultraviolet luminescence at ~380 nm. Band gap values were found from UV peak position between 3.25 – 3.28 eV. Relative intensity of defect related peaks between 400–700 nm in photoluminescence spec...
Journal of Materials Engineering and Performance, 2020
Journal of Materials Science: Materials in Electronics, 2019
Electronic Materials Letters, Jul 26, 2020
Applied Physics A, Nov 1, 2019
This paper presents the role of the conventional and Soliton wave model deposition at low substra... more This paper presents the role of the conventional and Soliton wave model deposition at low substrate temperature (300-100 K) on the structural, electric and magnetic properties of Co 35 Fe 65 thin films deposited by thermal evaporation using bulk polycrystalline Co 35 Fe 65 alloy. On account of obtaining superior quality magnetic thin films without any high temperature growth processes or heat treatment, the Soliton wave growth model at suitable low temperature range is used. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are employed to investigate the various structural properties. Morphological and structural analyses of entire 30 nm Co 35 Fe 65 thin films deposited on Si (100) substrate reveal that the stoichiometry is preserved over the whole temperature deposition and BCC crystalline formed with (110) texture. To attain the electrical and magnetic properties, resistivity and vibrating-sample magnetometer (VSM) measurements are evaluated. Soliton wave model deposition significantly increased magnetic anisotropy constant K 1 = 0.105 Merg/cm 3 , M R /M S = 0.83 and coercivity H C = 272 Oe at 300 K when the compared to conventional deposition range in this work (K 1 = 0.014 Merg/cm 3 , M R /M S = 0.6 and H C = 50 Oe). Growth with novel approach of Co 35 Fe 65 thin films highlights the reasonable low coercivity, the high saturation magnetization, the high magnetic anisotropy and the low electrical resistivity values, with tailored grain size, make them feasible to use in magnetic sensor technology in the near future.
Gazi University Journal of Science
Here, Turkish human hair fibers were used as a carbon source at the synthesis of human hair-sourc... more Here, Turkish human hair fibers were used as a carbon source at the synthesis of human hair-sourced activated carbons (HHC). During the synthesis of HHCs sodium carbonate (Na2CO3) was added to the synthesis process for an elevated activation by calcination at different temperatures. Then obtained HHCs utilized for the modification of carbon paste electrode to evaluate the supercapacitance performance of this activated HHC. Electrochemical investigation of the HHC modified electrodes have been carried out by employing differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The pore and surface properties and chemical structure of the HHCs were investigated by scanning electron microscopy (SEM), Brunauer-Emmett and Teller (BET) analysis and Raman spectroscopy. HHCs displayed a Type-IV isotherm, which indicates the existence of micro-mesoporous structure on the surface. Carbonization of the waste hair was performed by...
Journal of Radioanalytical and Nuclear Chemistry
Semiconductor Science and Technology, 2021
In this study, two different n-CdS/p-Cu2S solar cells were prepared by evaporating Cu at differen... more In this study, two different n-CdS/p-Cu2S solar cells were prepared by evaporating Cu at different substrate temperatures (200 K and 300 K) by vacuum evaporation method on a single crystal CdS semiconductor. Field emission scanning electron microscope images showed that the Cu layer obtained at a temperature of 200 K was composed of nanoparticles in accordance with the soliton growth mechanism. Cu film thickness was determined as 395 ∓ 0.76 nm at 300 K substrate temperature and 187 ∓ 0.45 nm at 200 K substrate temperature. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the solar cells were examined for 12 weeks in dark and light environments. Open-circuit voltage (V oc), short-circuit current (I sc), maximum power (P max), filling factor and efficiency (η) were calculated from I–V measurements. For the prepared solar cells, the highest efficiency value was obtained in the 7th week (η= 0.1360) at 200 K substrate temperature, while it was obtained in the 5t...
El-Cezeri Fen ve Mühendislik Dergisi, 2020
In this study, graphene oxide was synthesized from activated carbon obtained from waste hair for ... more In this study, graphene oxide was synthesized from activated carbon obtained from waste hair for the first time using Modified Hummers method. the Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy and X-Ray Diffraction (XRD) analysis results of synthesized graphene oxide were examined. In SEM images, graphene oxide structures were observed as very thin layers. In addition, the characteristic peaks of graphene oxide were observed in FT-IR spectroscopy and Raman spectroscopy. In the XRD spectra, reflections of the graphene oxide were seen in plane (001) at 2θ=13.66. It was determined that this structure was hexagonal crystal structure. The distance d (6.39Å) between the planes and the weave parameters were determined to be 12.80 Å. The transformation process for actived carbon production from human hair waste was patented by Turkish Patent and Trademark Office (Turkish Patent Institute Application Number: (2017/10764).
Journal of Alloys and Compounds, 2014
ABSTRACT Chemical bath deposition method was used for preparation of Cd1-xCoxS thin films. The ef... more ABSTRACT Chemical bath deposition method was used for preparation of Cd1-xCoxS thin films. The effects of Co doping and thermal annealing on structural, optical, electrical and magnetic properties of CdS thin films were investigated. X-ray diffraction studies showed that the textures of all Cd1-xCoxS thin films were cubic with (1 1 1) preferred direction. It was determined from Scanning electron microcopy micrographs that grain size of the samples was found to be around 150 nm. Optical transmittance of the CdS thin films decreased from similar to 85% to similar to 65% with Co doping. It was observed from photoluminescence spectra that all samples had two broad peaks around 380-500 nm and 520-700 nm. The resistivity value of Co doped samples was higher than that of undoped CdS. The undoped and Co doped CdS thin films showed a ferromagnetic behavior at room temperature.
Applied Surface Science, 2006
Asphalt (cheap and available in huge amount in Jordan) was converted into activated carbon powder... more Asphalt (cheap and available in huge amount in Jordan) was converted into activated carbon powder by chemical treatment with sulphuric and nitric acids at 450°C. The final product was characterized and found effective as adsorbent material. Its cation exchange capacity reaches 191.2meq/100-g carbons when treated with 30wt% acid/asphalt ratio without airflow rate injection and 208meq/100-g carbons when 6.5ml air/min was
International Journal of Environmental Analytical Chemistry, 2022
J. Mater. Chem. A, 2016
Although Cu2S-containing chalcogenide solar cells are appealing and cost-effective for photovolta... more Although Cu2S-containing chalcogenide solar cells are appealing and cost-effective for photovoltaics (PVs), these materials suffer from rapid performance degradation as a result of the diffusion of copper ions into the CdS layer.
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Papers by Vagif Nevruzoglu