Browsing by Author "Turgut, G."

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The Characteristic Investigation of Spray Coated W Incorporated in Oxide Thin Films
(Pleiades Publishing Inc, 2016) Turgut, G.; Keskenler, E. F.
W incorporated tin oxide (TO) thin films were grown via spray pyrolysis with various tungsten contents. The films were observed to be polycrystalline tetragonal crystal nature with (301) and (211) preferential planes. From EDX analysis, it was seen the tungsten concentrations in the TO films were slightly higher than ones in the starting solutions. Polyhedron-like and small rod like grains were observed in the SEM images. 3 at % W doped tin oxide film has minimum sheet resistance (44.67 Ohm) and resistivity (3.685 x 10(-3) Ohm cm) values and maximum figure of merit (75.74 x 10(-5) Ohm(-1)) value. The optical band gap (E (g) ) of pure film raised from 3.84 to 3.91 eV with 3 at % W contribution level.
The Effect of Eu-Loading on the Some Physical Features of CdO
(Elsevier Sci Ltd, 2018) Turgut, G.; Aksoy, G.; Iskenderoglu, D.; Turgut, U.; Duman, S.
The Eu-loaded CdO thin films were coated on the glass substrates with a sol-gel spin coating method by using Cd (CH3COO)(2)center dot H2O and EuCl3 center dot 6H(2)O salts. The effect of Eu-loading ratio varied from 0 to 4 at% in the step of 1 at% on the structural, morphological, electrical, and optical features of cadmium oxide had been evaluated with XRD, Raman study, SEM, AFM, Four Point Probe, and UV/VIS analysis. The coated films were polycrystalline with (111) preferential orientation and they had a cubic cadmium oxide structure. The granular-structure was observed from SEM and AFM images. The sizes of granules were in the range of 15-220 nm. It was observed that the homogeneity of granule distribution deteriorated with Eu-content. The RMS roughness value increased from 4.1nm to 284 nm with Eu-doping. The minimum sheet resistance was found to be 4.8 x 10(2) Omega for 2 at% Eucontent, but the maximum optical band gap was determined to be 2.61 eV for 1 at% Eu-content. The Urbach energy varied between 366 meV and 658 meV. As a result of this work, Eu-doping has an important effect on the properties of cadmium oxide.
Effect of Ta Doping on the Characteristic Features of Spray-Coated SnO2
(Elsevier Science Sa, 2015) Turgut, G.
In present work, undoped and Ta-doped SnO2 thin films were fabricated via a simple and cheap spray pyrolysis technique. The Ta-doping level was varied from 0 at.% to 5 at.% in the step of 1 at.%. Large pyramidal and small densely-packed tetragonal SnO2 particles were observed by X-ray diffraction and scanning electron microscope. Atomic force microscope analysis indicated that root mean square roughness values of films changed from 26.7nmto 51.6 nm with Ta-doping. The electrical and optical measurements revealed that the films had a degenerate n-type semiconductor property. The resistivity, sheet resistance, carrier concentration, mobility, and optical band gap values of films varied between 1.11 x 10(-2) Omega cm-2.35 x 10(-3) Omega cm, 130.66 Omega/square -26.97 Omega/square, 2.72 x 10(19) cm(-3)-1.12 x 10(20) cm(-3), 20.68 cm(2) V-1 s(-1)-30.78 cm(2) V-1 s(-1), and 3.43 eV-3.94 eV, respectively. As a result of this study, it is concluded that characteristic properties of SnO2 can be greatly improved with Ta-doping. (C) 2015 Elsevier B.V. All rights reserved.
Electrical Properties of Al/P-Ge and Al/Methyl Green/P-Ge Diodes
(Taylor & Francis Ltd, 2015) Duman, S.; Turgut, G.; Ozcelik, F. S.; Gurbulak, B.
Methyl green (MG) film has been grown for the first time on p-Ge semiconductor using a simple and low-cost drop coating method. The current-voltage (I-V) characteristics of Al/p-Ge and Al/MG/p-Ge diodes have been investigated in the temperature range of 20-300K. A potential barrier height as high as 0.82eV has been achieved for Al/MG/p-Ge diode, which has high rectification rate, at room temperature. It is seen that the barrier height of the Al/MG/p-Ge diode at the room temperature is larger than that of Al/p-Ge diode and ideality factor value of 1.14 calculated for Al/MG/p-Ge diode is lower than Al/p-Ge diode. The temperature coefficient of barrier height of the Al/MG/p-Ge diode has been calculated as 2.6meV/K. The evaluation of current-voltage characteristics shows that the barrier height of the diode increases with the increasing temperature.
Europium Incorporation Dynamics Within NiO Films Deposited by Sol-Gel Spin Coating: Experimental and Theoretical Studies
(Pergamon-Elsevier Science Ltd, 2019) Goumri-Said, Souraya; Khan, Wilayat; Boubaker, Karem; Turgut, G.; Sonmez, E.; Minar, Jan; Kanoun, Mohammed Benali
Europium doped NiO thin films were grown onto glass substrates via sol-gel spin coating. The evolution of crystal structure, surface topography, and optical properties of NiO was investigated as a function of Eu doping concentration. AFM observations and XRD analysis revealed that NiO:Eu films composed of nano-sized grains exhibit a polycrystalline cubic bunsenite structure with (200) preferential orientation. Optical study showed that the optical band gap of doped NiO films initially increased with low Eu incorporation ratio then decreased with higher Eu content. However, the Urbach energy increased gradually with Eu doping level. First principle calculations were performed to elucidate the changes on electronic, magnetic and optical properties of NiO due to Eu doping. The incorporation of Eu within NiO host lattice induced a strong hybridization between Eu-f and Ni-d states resulting in important changes of bulk magnetization.
Evaluation of Nd-Loaded SnO2:F Films Coated Via Spray Pyrolysis
(Springer, 2018) Turgut, G.
Thin layers of single (F)- and double (F/Nd)-incorporated tin oxide have been coated on glass substrate via spray pyrolysis. The structural, morphological, electrical, and optical features of F-incorporated samples were evaluated depending on the Nd loading. X-ray diffraction analysis revealed that samples had tetragonal tin oxide structure with (211) and (200) preferential directions. The crystallite size and strain values varied from 37.98 nm and 1.21 x 10(-3) to 52.12 nm and 1.88 x 10(-3). Scanning electron microscopy analysis showed that the samples consisted of pyramidal, polyhedral, and needle-shaped granules. The lowest sheet resistance value of 1.22 Omega was found for 1.8 at.% Nd + 25 at.% F-coloaded SnO2. However, the widest optical bandgap of 4.01 eV was observed for the single 25 at.% F-loaded sample. The Urbach tail and figure of merit also changed in the ranges of 664 meV to 1296 meV and 6.4 x 10(-2) a"broken vertical bar(-1) to 2.3 x 10(-3) a"broken vertical bar(-1), respectively. The results presented herein indicate that the character of F-doped tin oxide films can be controlled by Nd loading and that these films could be useful for technological applications.
Fabrication and Characterization of N-ZnO/P-GaAs Structure
(Springer, 2018) Turgut, G.; Kaya, F. S.; Duman, S.
In this investigation, n-ZnO/p-GaAs structure is prepared by a sol-gel route. ZnO film has wurtzite structure with (101) preferential direction. The nano-sized particles are homogeneously dispersed on the film surface. The root mean square roughness and optical band gap values are determined to be 11.49 nm and 3.272 eV. The electrical study shows that n-ZnO/p-GaAs structure has a rectifying property under the dark. The ideality factor and barrier height of structure are defined to be 1.52 and 0.92 eV, respectively. As a result of present work, n-ZnO/p-GaAs structure can be used in a variety of electronic applications.
The Influence of Y Contribution on Crystallographic, Topographic and Optical Properties of ZnO: A Heterojunction Diode Application
(Academic Press Ltd- Elsevier Science Ltd, 2015) Turgut, G.; Duman, S.; Keskenler, E. F.
Pure and yttrium (Y) doped ZnO samples were fabricated on micro slide glasses and p-Si wafers for device application via a simple and cheap sol-gel route using a spin coater. The characterization results of XRD, SEM and UV/VIS spectrophotometer revealed the films to have nano-sized ZnO hexagonal wurtzite structures with (002) preferential orientation and optical band gap values depending on Y doping ratio. The optical band of 3.285 eV for pure ZnO initially increased to 3.305 eV, 3.332 eV and 3.341 eV for 1 at.%, 2 at.% and 3 at.% Y incorporated ZnO films and then decreased to 3.271 eV and 3.258 eV for 5 at.% and 7 at.% Y contents. The electrical features of Al/ZnO:Y/p-Si/Al heterojunction structures were tested by I-V measurements. The heterojunction structures showed a rectifying behavior under dark condition. The Phi(b), and n values for the devices were identified by using I-V measurements. It was observed that the rectification ratio value of 3 x 10(4) calculated at +3.0 V for Al/ZnO:Y/p-Si (5 at.% Y doped ZnO) heterojunction structure was higher than most of n-ZnO/p-Si heterojunction devices reported in the literature. (C) 2015 Elsevier Ltd. All rights reserved.
Investigation of Characteristic Properties of Pr-Doped SnO2 Thin Films
(Taylor & Francis Ltd, 2015) Turgut, G.
In the present work, an investigation study on the crystal structure, surface morphology, electrical conductivity and optical transparency of spray-deposited Pr-doped SnO2 was made as a function of Pr doping content. The X-ray diffraction studies indicated that the films were grown at the (211) preferential orientation. The values of crystallite size and strain were determined using Williamson-Hall method and they varied between 71.47 and 208.76nm, and 1.98x10(-3)-2.78x10(-3). As seen from Scanning Electron Microscope micrographs, the films were composed of homogenous dispersed pyramidal-shaped grains. The n-type conductivity of films was confirmed with Hall Effect measurements, and the best electrical parameters were found for 3at.% Pr doping level. The highest optical band gap and transmittance values were observed for undoped SnO2 sample. The highest figure of merit (phi), which is a significant parameter to interpret the usage efficiency of conductive and transparent materials in the optoelectronic and solar cell applications, was calculated to be 2.85x10(-5)ohm(-1) for 1at.% Pr doping content. As a result of this study, it may be concluded that Pr-doped SnO2 films with above properties can be used as a transparent conductor in various optoelectronic applications.
An Investigation of Pb-Contribution Effect on the Characteristic Features of CdO Films Coated with a Sol-Gel Spin Coating Technique
(Springer, 2017) Turgut, G.
Lead (Pb)-loaded CdO films have been firstly fabricated with a sol-gel spin coating apparatus. Pb-contribution ratio was changed from 0 to 5 at.% in the step of 1 at.%. The impact of Pb-contribution ratio on the crystalline, surface, and optical characters of CdO was examined with XRD, XPS, SEM, AFM, and UV/VIS spectrophotometer measurements. The polycrystalline cubic CdO nano-particles with (111) preferential direction were observed for the whole samples. Although the value of average crystallite size of pure CdO continuously increased with Pb-loading, the dislocation density value decreased with Pb-contribution content. The nano-sized spherical granules with a c-axis columnar structure were also seen from SEM and AFM images. The RMS roughness values were found to be an increasing tendency from 5.97 to the values of 8.28 nm, 8.89, 17.9, 22.7, and 39.3 nm with Pb-loading content. The optical studies showed that the band gap and Urbach energy values of pure CdO initially increased from 2.61 eV and 371 meV to 2.76 eV and 390 meV with 3 at.% Pb-content, then they went down with more Pb-contents. As a result of this investigation, it can be concluded that Pb-contribution level has a significant influence on the properties of CdO.
Investigation of Physical, Electrical and Optical Properties of Sol-Gel Deposited Sc-Loaded CdO Films
(Elsevier Gmbh, Urban & Fischer Verlag, 2017) Turgut, G.; Tatar, D.
For the first time, Sc-loaded CdO thin layers have been deposited with a sol-gel process by using Cd(CH3COO)(2)center dot 2H(2)O and ScCl3 salts. The Sc-contribution effect on the crystalline, surface, electrical, and optical features have been inquired by means of XRD, AFM, SEM, Four Probe method, and UV/VIS spectrophotometer. The polycrystalline cubic CdO nano-particles with (111) preferential direction were observed from XRD studies. The average crystallite size, micro-strain values of Sc-loaded CdO samples changed between 22.05-17.16 nm and 2.46 x 10(-3)-3.16 x 10(-3). The SEM and AFM images indicated that CdO samples have been composed of nano-sized spherical particles. The most homogeneous particle distribution was observed for 1 at.% Sc-contribution level and the particle sizes of pure and Sc-loaded CdO samples varied between about 30-200 nm. The sheet resistance values of films were found in the range of 5.0 x 10(3) Omega and 2.1 x 10(2) Omega. The optical transmittance and reflectance values for samples have been found between 65 and 90% and 5-22% over visible region. The optical band gap for pure CdO firstly went up from 2.63 eV to 2.66 eV with 1 at.% Sc-doping ratio and then it continuously decreased. The Urbach tail, extinction coefficient, dielectric constant and refractive index values were also determined as depending on Sc-doping content. As a result of the present research, it was seen the Sc-contribution level affected the crystallite size, lattice constant, micro-strain, optical band gap and sheet resistance values of CdO. (C) 2017 Elsevier GmbH. All rights reserved.
An Investigation of Spray Deposited CdO Films and CdO/P-Si Heterojunction at Different Substrate Temperatures
(Springer, 2021) Turgut, G.; Aydogan, S.; Yilmaz, M.; Ozmen, A.; Kacus, H.
In this study, CdO films were successfully obtained by using a homemade chemical spray pyrolysis technique. The crystal structures of the CdO thin films improved due to an increase in the substrate temperature when the spray time was kept constant. Additionally, CdO film deposited at 250 degrees C exhibited amorphous crystal structure. The surface morphology of the samples was evaluated by scanning electron microscope (SEM) and it was observed that well-defined granules started to be clearly seen when the substrate temperature increased. Optical properties of CdO films were also investigated by using an ultraviolet-visible (UV-Vis) spectrophotometer, and the optical band gap of CdO varied from 2.57 eV to 2.73 eV with increasing substrate temperature. The electrical performance of the CdO films in the Au/CdO/p-Si device were determined by I-V measurements. According to the results, it was found that diode parameters depend on the changing properties of CdO in terms of the substrate temperature.
An Investigation of Spray Deposited Cdo Films and Cdo/P-si Heterojunction at Different Substrate Temperatures (Vol 73, Pg 566, 2021)
(Springer, 2021) Turgut, G.; Aydogan, S.; Yilmaz, M.; Ozmen, A.; Kacus, H.
This article was corrected to remove extraneous units of eV for ideality factor introduced during the production process.
Investigations on the Crystalline, Topographic, Electrical and Optical Characteristics of Doubly Doped (Si + F) SnO2 Films Deposited Using Spray Pyrolysis Technique
(Academic Press Ltd- Elsevier Science Ltd, 2015) Turgut, G.; Thirumurugan, K.; Ravichandran, K.
Silicon and fluorine (Si + F) co-doped SnO2 thin films were deposited on soda lime glass substrate using the spray pyrolysis technique. The Si and F doping levels were varied from 0-10 and 2.5-10 in steps of 2.5 at. %, respectively. Initially the optimum doping level of Si is found (7.5 at. %) at which the film exhibits the minimum electrical resistivity value (4.23 x 10(-3) Omega cm) and then the doping level of F is varied and it is found to be better at 10 at. % on which it offers lower resistivity of 1.96 x 10(-4) Omega cm. From the structural studies, it is observed that the preferential orientation of all the films is along (2 1 1) plane irrespective of dopant and level of doping, but the peak intensity decreases as the doping level increases. The average transmittance of the all the films is found to be around 75% in the visible region and the optical band gap of the films are found to be in the region of 3.79-3.99 eV. (C) 2015 Elsevier Ltd. All rights reserved.
Lutetium Incorporation Influence on ZnO Thin Films Coated via a Sol-Gel Route: Spin Coating Technique
(Springer, 2016) Turgut, G.; Duman, S.; Ozcelik, F. S.; Gurbulak, B.; Dogan, S.
Pure and lutetium (Lu) incorporated zinc oxide (ZnO) thin films were deposited by a sol-gel route. The effect of Lu contribution on the properties of ZnO was examined in detail by means of XRD, AFM, SEM, UV-Vis spectrophotometer, and I-V measurements. The nano-sized ZnO:Lu samples had hexagonal wurtzite structure with c-axis (002) preferential orientation. The pure ZnO nano-particles homogeneously scattered on the film surface and this homogeneous particle distribution was deteriorated with Lu incorporation. Ohmic contacts to the ZnO:Lu films were formed using gold (Au) metallization schemes. As-deposited Au contacts exhibited linear current-voltage characteristics. The optical band gap for pure ZnO went up from 3.281 to 3.303 eV with low Lu contribution level up to 3 at.%, then it decreased with more Lu level. The Urbach energy was also studied and it was found that E-u depended on Lu incorporation level.
Silicon-Doping Influence on the Crystalline, Surface and Optical Features of Cadmium Oxide Films Deposited by Sol-Gel Spin Route
(Elsevier GmbH, 2018) Turgut, G.; Kurt, M. S.; Ertugrul, M.; Iskenderoglu, D.; Duman, S.; Gurbulak, B.
This is the first study on Si-contributed CdO films fabricated via sol-gel process. Si-doping impact on the crystalline, topographic and optical qualities of cadmium oxide has been searched with XRD, SEM, AFM and UV/vis spectrophotometer. The whole films were polycrystalline with (111) preferential direction and the crystalline degree of CdO depended on Si-contribution effect. The crystallite size of undoped-CdO incessantly decreased with Si-content, however dislocation density increased with Si-level. The spherical CdO granules were nanoscale and their sizes varied between 20-170 nm. The RMS roughness values of films changed between 5.84 nm-40.5 nm. The optical gap value of undoped-CdO continuously declined from 2.59 eV to 2.39 eV with increasing Si-content, while the Urbach energy increased from 350 meV to 468 meV with Si-level. These results reveal that the level of Si-doping affect the features of cadmium oxide. (C) 2018 Elsevier GmbH. All rights reserved.
Sol-Gel Growth and Characterization of a New P-NiO/N-GaAs Structure
(Elsevier Science Sa, 2016) Turgut, G.; Duman, S.
A new p-NiO/n-GaAs heterostructure was fabricated by a simple and cheap sol-gel route. X-ray diffraction, atomic force microscope and UV/VIS studies indicated that nano-sized NiO film had poly-crystalline cubic bunsenite crystal structure with optical band gap of 3.75 eV. The energy dispersive x-ray mapping analysis proved the homogenous distribution of nickel and oxygen elements on GaAs surface. The electrical characterization of p-NiO/n-GaAs structure showed a rectifying behavior with rectification ratio 3.3 x 10(4) at +2.0 V in the dark for p-NiO/n-GaAs structure. The ideality factor and barrier height were calculated as 2.21 and 0.76 eV. The results suggest that p-NiO/n-GaAs structure can be used in many electronic applications. (C) 2016 Elsevier B.V. All rights reserved.
A Study of Eu Incorporated ZnO Thin Films: An Application of Al/ZnO:Eu Heterojunction Diode
(Elsevier, 2016) Turgut, G.; Duman, S.; Sonmez, E.; Ozcelik, F. S.
In present work, the pure and europium (Eu) incorporated zinc oxide (ZnO) thin films were deposited with sol-gel spin coating by using zinc acetate dehydrate and Eu (III) chloride salts. The coated films were examined by means of XRD, AFM and UV/VIS spectrophotometer. The ZnO hexagonal wurtzite nanoparticles with (002) preferential direction were observed for all films. The values of crystallite size, micro-strain and surface roughness continuously increased from 21 nm, 1.10 x 10(-3) and 2.43 nm to the values of 35.56 nm, 1.98 x 10(-3) and 28.99 nm with Eu doping, respectively. The optical band gap value of the pure ZnO initially increased from 3.296 eV to 3328 eV with Eu doping up to 2 at.% doping level, then it started to decrease with more Eu content. The electrical features of Al/n-ZnO:Eu/p-Si heterojunction diodes were inquired by current-voltage (I-V) measurements at the room temperature. 2016 Elsevier B.V. All rights reserved.
A Study on Investigation of Electrical Properties of Au/Chlorophyll-a Structure
(Elsevier, 2023) Kaya, F. S.; Duman, S.; Turgut, G.
The chlorophyll-a (Chl-a) thin film has been formed on the n-Si substrate using a spin-coater. The electrical properties of the Au/Chl-a/n-Si/Al structure have been examined with the data obtained from the current-voltage (I-V) measurements in the dark and under illumination at room temperature. The ideality factor (n) and barrier height (phi b) values have been calculated as 1.24 and 0.799 eV in the dark and 1.08 and 0.824 eV in daylight at room temperature. Also, I-V measurements were taken under different illuminations, and some photoelectrical parameters of the Au/Chl-a/n-Si/Al structure, such as photocurrent, photosensitivity, and Ion/Ioff, were investigated. The results show that the Chl-a thin film can be utilized to fabricate photodiodes and solar cells.
Synthesis and Investigation of Some Physical Properties of Pure and Ho-Loaded ZnO Nano-Rods
(Springer Heidelberg, 2019) Aydin, S.; Turgut, G.
In this research, pure and Ho-loaded zinc oxide nano-rods have been synthesized with the sol-gel spin coating way. The impact of holmium-loading content changed between 0-4 at.% in step of 1 at.% on the structural, vibrational, surface, and optical characters was inquired. The hexagonal ZnO nano-rods with (002) and (101) preferential orientations were seen from SEM and XRD analyses. It was found that the surface character of ZnO nano-rods depended on Ho-loading content. The UV and green emission bands were observed from PL analysis. A blue shift with low-content Ho level was seen from UV/Vis spectrophotometer and PL measurements. The optical band-gap value primarily raised from 3.32 to 3.40 eV for low Ho content, and then, it went down for more Ho loading. The present study gives that the physical features of zinc oxide are greatly healed with holmium loading.