Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(114)
- Kaya, Yunus(48)
- Şahin, Engin(48)
- İspirli, Hümeyra(47)
- Özen, Soner(38)
- Şenay, Volkan(37)
- Pat, Suat(36)
- Kutlu, Naciye(32)
- Artar, Musa(31)
- Can, Zehra(31)
- Korkmaz, Şadan(31)
- Yilmaz, Mustafa Tahsin(31)
- Öner, Erdal(31)
- Bayram, Sinan(30)
- Cuce, Erdem(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Ecem Bayram, Nesrin(28)
- Mercan, Emin(28)
- Ayata, Ümit(27)
- Bayraktar, Bülent(27)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Ayazoglu, Rabil(22)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Bayram, Ozkan(21)
- Kamiloğlu, Aybike(21)
- Dirican, Ebubekir(20)
- Kadakal, Mahir(20)
- Abdioglu, Murat(19)
- Birinci, Ahmet(19)
- Tozlu, Alperen(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Cinar, Mehmet(17)
- Gul, Volkan(16)
- Hasar, Ugur C.(16)
- Kadakal, Huriye(16)
- Kara, Yakup(16)
Yayınlar
- MakaleAçık Erişim2016Scopus SJRQ1Effects of in situ exopolysaccharide production and fermentation conditions on physicochemical, microbiological, textural and microstructural properties of Turkish-type fermented sausage (sucuk)
Dertli, Enes; Yilmaz, Mustafa Tahsin; Tatlisu, Nevruz Berna; Toker, Omer Said; Cankurt, Hasan; Sagdic, Osman
In this work, the role of in situ exopolysaccharide (EPS) production under different fermentation conditions on physicochemical, microbiological, textural and microstructural properties of sucuk was determined. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 14, 16 and 18 °C and time; 8, 12 and 16 days) on physicochemical, microbiological, textural and microstructural properties were investigated using response surface methodology. In situ EPS production was observed to remarkably affect these properties while fermentation conditions were also seen to dominantly influence the physicochemical properties of sucuk, revealing that the ripening temperature appeared to be more determinant factor. EPS producing cultures enhanced the textural properties of sucuk which became harder, less adhesive and tougher. The microstructural analysis revealed the formation of web-like structure by in situ EPS production in sucuk mix during fermentation process. This study revealed the importance of in situ EPS production on final technological properties of sucuk.
AtıfScopus48WoS43OpenAlex54
İncele - Derleme MakaleYalnız künye2016Scopus SJRQ1Renewable and sustainable energy saving strategies for greenhouse systems: A comprehensive review
Cuce, Erdem; Harjunowibowo, Dewanto; Cuce, Pinar Mert
In this study, a comprehensive review focusing on key strategies of energy saving and climate control technologies for greenhouses is presented. Following the brief and concise assessment of existing greenhouse systems in terms of their role in total energy consumption; cost-effective, energy-efficient and environmentally friendly technologies are analyzed in detail for potential utilization in greenhouses for notable reductions in energy consumption and emission levels. The technologies considered within the scope of this research are mainly renewable and sustainable based solutions such as photovoltaic (PV) modules, solar thermal (T) collectors, hybrid PV/T collectors and systems, phase change material (PCM) and underground based heat storage techniques, energy-efficient heat pumps, alternative facade materials for better thermal insulation and power generation (heat insulation solar glass, PV glazing, aerogel and vacuum insulation panel, polycarbonate sandwich panels), innovative ventilation technologies using pre-heating and cooling (high performance windcatchers) and efficient lighting systems. The findings from the research clearly reveal that up to 80% energy saving can be achieved through appropriate retrofit of conventional greenhouses with a payback period of 4-8 years depending on climatic conditions and crop type.
AtıfScopus354WoS302OpenAlex382İncele - MakaleYalnız künye2016Scopus SJRQ1Optimum design of braced steel frames via teaching learning based optimization
Artar, Musa
In this study, optimum structural designs of braced (non-swaying) planar steel frames are investigated by using one of the recent meta-heuristic search techniques, teaching-learning based optimization. Optimum design problems are performed according to American Institute of Steel Construction-Allowable Stress Design (AISCASD) specifications. A computer program is developed in MATLAB interacting with SAP2000 OAPI (Open Application Programming Interface) to conduct optimization procedures. Optimum cross sections are selected from a specified list of 128W profiles taken from AISC. Two different braced planar frames taken from literature are carried out for stress, geometric size, displacement and inter-storey drift constraints. It is concluded that teaching-learning based optimization presents robust and applicable optimum solutions in multi-element structural problems.
AtıfScopus25WoS26İncele - MakaleAçık Erişim2016Scopus SJRQ1A New Energy Prediction Algorithm for Energy-Harvesting Wireless Sensor Networks With Q-Learning
Kosunalp, Selahattin
Traditional wireless sensor networks (WSNs) face the problem of a limited-energy source, typically batteries, resulting in the need for careful and effective utilization of the energy source. However, inevitable energy depletion will eventually disturb the operation of a WSN. Energy harvesting (EH) technology is acquiring particular interest, because it has the potential to provide a continuous energy supply in battery-powered WSNs. Solar energy is the most effective environmental energy for EH-WSNs because of its high energy intensity, which comes from a non-controllable source. Therefore, the prediction of future energy availability is a critical issue, as the amount of the harvestable energy may vary over time. In this paper, a novel solar energy prediction algorithm with Q-learning, called Q-learning-based solar energy prediction (QL-SEP), is proposed. Q-learning is an effective way of predicting future actions based on past observations. The distinctive feature of QL-SEP is that not only past days' observations but also the current weather conditions are considered for prediction. The performance of QL-SEP is simulated in this paper using real-world measurements obtained from a solar panel in comparison with the state-of-art approaches.
AtıfScopus128WoS96OpenAlex135İncele - MakaleYalnız künye2016Scopus SJRQ2Surface and optical properties of indium tin oxide layer deposition by RF magnetron sputtering in argon atmosphere
Yudar, H. Hakan; Korkmaz, Şadan; Özen, Soner; Şenay, Volkan; Pat, Suat
This study focused on the characterization and properties of transparent and conductive indium tin oxide (ITO) thin films deposited in argon atmosphere. ITO thin films were coated onto glass substrates by radio frequency (RF) magnetron sputtering technique at 75 and 100 W RF powers. Structural characteristics of producing films were investigated through X-ray diffraction analysis. UV–Vis spectrophotometer and interferometer were used to determine transmittance, absorbance and reflectance values of samples. The surface morphology of the films was characterized by atomic force microscope. The calculated band gaps were 3.8 and 4.1 eV for the films at 75 and 100 W, respectively. The effect of RF power on crystallinity of prepared films was explored using mentioned analysis methods. The high RF power caused higher poly crystallinity in the produced samples. The thickness and refractive index values for all samples increased respect to an increment of RF power and were calculated as 20, 50 nm and 1.71, 1.86 for samples at 75 and 100 W, respectively. Finally, the estimated grain sizes for all prepared films decreased with increasing of 2θ degrees, and the number of crystallite per unit volume was calculated. It was found that nearly all properties including sheet resistance and resistivity depend on the RF power.
AtıfScopus11WoS10OpenAlex11İncele - MakaleYalnız künye2016Scopus SJRQ1Clarification of magnetic levitation force and stability property of multi-seeded YBCO in point of supercurrent coupling effect
Ozturk, K.; Kabaer, M.; Abdioglu, M.; Patel, A.; Cansiz, A.
In our study as different from the literature, which are mostly related to superconductor fabrication, application and optimization, especially physical origins of bulk supercurrent generation, magnetic levitation and stability properties of the multi-seeded YBCO superconductor are investigated in point of supercurrent coupling effect. Besides the experimental measurements, a simplified simulation of the supercurrent coupling in the multi-seeded bulk YBCO is carried out based on the experimental J(c)(B) data taken from literature and using the critical state method and H-formulation together in COMSOL Multiphysics package, to further elucidate the mechanism of supercurrent generation and guidance force. The bigger guidance force and lateral magnetic stiffness values of PMG-B arrangement with three B-z peaks than the other arrangements with one Bz peak in small cooling height of 5 mm are attributed to the more robust individual intragrain supercurrents, rather than intergrain supercurrent, due to the position coincidence in the z-direction between grains and permanent magnet poles. Additionally, it can be said that PMG-C arrangement with one Bz peak getting to the maximum guidance force value when the cooling height increase from 5 mm to 15 mm, points out for large cooling height the intergrain supercurrents dominate, whereas for the small cooling height the intragrain supercurrents have most effect on the guidance force. Also, performed the supercurrent simulations, using different current flow constraint ratio f (or supercurrent coupling parameter), clearly reproduced the qualitative change in the trapped field profile when the allowed intergrain current compared to no intergrain current (f = 0). It is thought that the presented results, related to the supercurrent generation, coupling mechanism and their effect on levitation and lateral force properties, have utilization potential for researches not only they study on new multiseed superconductor fabrication method, but also they study on superconductor applications. (C) 2016 Elsevier B. V. All rights reserved.
AtıfScopus29WoS30OpenAlex30İncele - MakaleAçık Erişim2015Optical, Structural and Morphological Characterization of a Zn-Doped GaAs Semiconducting Thin Film Produced by Thermionic Vacuum Arc
Senay, Volkan; Özen, Soner; Pat, Suat; Korkmaz, Sadan
A 780 nm thick Zn-doped GaAs p-type semiconducting film was deposited onto a glass substrate under a high vacuum condition by means of the thermionic vacuum arc technique in a very short period of time (90 sec) using GaAs and Zn pellets as source materials. In order to characterize the produced film, the optical constants and absorbance of the film were measured using optical methods. By using the obtained optical absorbance data, the optical band gap was estimated from the Tauc plot based on the relation (alpha hv)(2) = B(hv - E-g). The refractive index value of the film was 3.73 at lambda = 632.8 nm. The band gap was estimated to be 1.35 eV. According to the results obtained from the FESEM and AFM related studies, the produced film displayed a granular surface morphology with a root mean square roughness of 17 nm. Contact angle measurements of several testing liquids were used to characterize the film in terms of wettability. It was found that the contact angle value was dependent on the liquid used. However, the film was hydrophilic as observed in contact angle measurements.
AtıfWoS3OpenAlex3İncele - MakaleYalnız künye2015Scopus SJRQ1THE IMPORTANCE OF DIALOGUE IN TURKEY
Cetinkaya, Kenan
- MakaleAçık Erişim2015INVESTIGATION OF RELIABILITIES OF BOLT DISTANCES FOR BOLTED STRUCTURAL STEEL CONNECTIONS BY MONTE CARLO SIMULATION METHOD
Öztekin, Ertekin
Design of the distance of bolts to each other and design of the distance of bolts to the edge of connection plates are made based on minimum and maximum boundary values proposed by structural codes. In this study, reliabilities of those distances were investigated. For this purpose, loading types, bolt types and plate thicknesses were taken as variable parameters. Monte Carlo Simulation (MCS) method was used in the reliability computations performed for all combination of those parameters. At the end of study, all reliability index values for all those distances were presented in graphics and tables. Results obtained from this study compared with the values proposed by some structural codes and finally some evaluations were made about those comparisons. Finally, It was emphasized in the end of study that, it would be incorrect of the usage of the same bolt distances in the both traditional designs and the higher reliability level designs.
AtıfWoS1OpenAlex3İncele - MakaleYalnız künye2015Isnad Criticism of the Narrative About Tanning Leather and Evaluation About the Usage of Pigskin
Aydin, Nevzat
It is need to explain what is meant in the hadiths which states that it is possible to use animal skin (dibagat) through tanning it. Especially in the context of this hadith, the issue that whether tanning leathers' of animals which are prohibited to eat such as pigs makes them clean has become subject for discussions. Another subject is whether they become clean for clothing and textiles. In this study, firstly hadith narrations are analyzed whether they are authorized in terms of their isnads. Then related hadiths are examined within the context of the Qur'an and Sunnah. Even though the issue is not discussed within Islamic law, views of madhabs are also touched on. Based on the account and the textual analysis it is showed that the view that tanning of pigskin does not make it clean, so in any case it cannot be cleaned and used, except the case of high necessity.
- MakaleYalnız künye2015Scopus SJRQ1Thermoeconomic optimization of gas turbine cogeneration plants
Karaali, Rabi; Öztürk, Ilhan Tekin
In this study, a novel thermoeconomic optimization method that is simple and efficient, for real complex cycles is introduced. First, a thermoeconomic analysis method that is called non-linear simplex direct search method is improved for the purposes of this study. The objective of this paper is to apply this method to four cogeneration cycles that are simple cycle, inlet air cooling cycle, air preheated and air-fuel preheated cycles for analyzing and optimizing. The four cycles are thermoeconomically optimized for constant power and steam mass (30 MW and 14 kg/s saturated steam flow rate at 2000 kPa), for constant power (30 MW) and for variable steam mass, and for variable power and steam mass by using the cost equation method and the effect of size on equipment method. The results obtained by the effect of size on equipment and by the cost equations methods are very different from each other. For the case of global optimization, the optimum electricity costs which also correspond to minimum are obtained as 0,0432 $/kWh for simple cycle, 0,0514 $/kWh for inlet air cooling cycle 0,0577 $/kWh for air preheated cycle and 0,058 $/kWh for air-fuel preheated cycle by using cost equations method. (C) 2014 Elsevier Ltd. All rights reserved.
AtıfWoS32OpenAlex39İncele - MakaleYalnız künye2015DAMAGE DETECTION IN SIMULATED SPACE FRAMES USING GENETIC ALGORITHMS
Artar, Musa; Daloglu, Ayse T.
Genetic algorithms (GA) based finite element model updating are applied to predict damage location and severity in space frames. The changes in natural frequencies are used as dynamic indicators to describe damaged members. Objective functions including dynamic data provide minimization of dynamic differences between numerical model and simulated damaged model. The presence of damages in structural elements is identified by stiffness reduction as a reduction in modulus of elasticity. Reproduction, double-point crossover and mutation operators are used in GA optimization procedures. In this paper, different simulated examples having various damage scenarios are modelled in SAP2000 software to obtain the experimental dynamic data. In the last example, noise effect is taken into account in simulated damaged data. A program is developed in MATLAB software for numerical model updating based on all genetic algorithm procedures. Thus, the size and extent of simulated damages are determined by updated numerical model. Results obtained from examples show that GA optimization is a convenient method for damage identification.
AtıfWoS2İncele - MakaleYalnız künye2015Scopus SJRQ4The Optimization of Multi-Storey Composite Steel Frames with Genetic Algorithm Including Dynamic Constraints
Artar, Musa; Daloglu, Ayse
Optimum design of the structures, in other words designing the structures with minimum weight is one of the major research areas in structural engineering. The priority during optimization process is to ensure whether the necessary conditions are satisfied or not. In this study, the optimization of steel frame systems is carried out for traditional and dynamic constraints by using a genetic algorithm that mimics the biological processes. The stress constraints are determined according to TS648-Turkish code for design and construction of steel structures. Furthermore, displacement constrains are considered in the optimization procedure. In addition, natural frequencies are incorporated as dynamic constraints. Optimum design of multi-story plane frames is obtained and comparisons with the results of previous studies are made. The same design processes are repeated for the case of frames with composite beams. A program is coded in MATLAB to carry out all these applications. Results obtained in the study for the frame systems are also verified by SAP2000. It is concluded that the weight of the frames with composite beams are fewer and the dynamic constraints affect the design.
AtıfWoS6İncele - MakaleYalnız künye2015Scopus SJRQ3Effect of Chemical Composition and Grain Size on RT Superplasticity of Zn-Al alloys processed by ECAP
Demirtas, M.; Purcek, G.; Yanar, H.; Zhang, Z. J.; Zhang, Z. F.
Dilute Zn-0.3Al, eutectic Zn-5Al and eutectoid Zn-22Al alloys were processed by multi-pass equal channel angular pressing (ECAP) in order to achieve fine grained (FG) or ultrafine-grained (UFG) microstructure and room temperature (RT) superplasticity. ECAP refined the microstructure of Zn-0.3Al and resulted in a FG Zn-rich.-matrix with an average grain size of 2 mu m and homogeneously distributed nano-sized Al-rich a-particles with the grain sizes in the range of 50-200 nm. A bi-modal microstructure was achieved in Zn-5Al alloy with UFG Al-rich a-and FG Zn-rich.-phases having mean grain sizes of 110 nm and 540 nm, respectively. ECAP brought about an agglomerate-free UFG microstructure in Zn-22Al alloy with an average grain size of 200 nm which is the lowest one obtained so far for this alloy after ECAP processing. The maximum RT superplastic elongations of 1000%, 520% and 400% were achieved for Zn-0.3Al, Zn-5Al and Zn-22Al alloys, respectively. Considering the RT superplasticity in Zn-Al alloys, it was found that lower Al content results in higher superplastic elongations even if the alloy has relatively larger grain size. Grain boundary sliding (GBS) was found to be the main deformation mechanism in region-II as the optimum superplastic region during RT deformation for all three Zn-Al alloys with the strain rate sensitivity factor ranging between 0.25-0.31.
AtıfWoS19İncele - MakaleAçık Erişim2015Scopus SJRQ1The Effect of pH and Temperature on Cabbage Volatiles During Storage
Akpolat, Hacer; Barringer, Sheryl Ann
During storage of shredded cabbage, characteristic sulfurous volatile compounds are formed affecting cabbage aroma both negatively and positively. Selected ion flow tube-mass spectrometry (SIFT-MS) was used to measure the concentration of cabbage volatiles during storage. The volatile levels of cabbage samples were measured at pH 3.3 to 7.4 at 4 degrees C for 14d, and pH 3.3 at 25 degrees C for 5d in order to determine the effect of pH and temperature. Aroma intensity, best aroma, freshness, and off odor were evaluated in a sensory test of the samples at 4 degrees C. The desirable volatile allyl isothiocyanate was lower in high pH samples (pH 7.4 and 6.4), whereas higher concentrations were detected in low pH samples (pH 3.3 and 4.6). Lipoxygenase volatiles, which produce a fresh green and leafy aroma in cabbage, were generated in very low amounts at any pH value. High pH samples generated significantly higher concentrations of off odors such as dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and methanethiol. Sensory tests showed that higher pH samples had significantly stronger off odor and lower desirable cabbage aroma than lower pH samples. Thus, sensory results matched the volatile results in that samples at higher pH levels formed the highest amount of undesirable volatiles and the least amount of desirable volatiles. Storage at 25 degrees C produced similar concentrations of allyl isothiocyanate, but significantly higher levels of off odors, than at 4 degrees C. Shredded cabbage products should be stored in low pH dressings to minimize formation of off odors and maximize formation of characteristic, desirable cabbage odor. Practical Application Low pH samples formed fewer undesirable, and more desirable volatile compounds overall. The natural pH of cabbage is around 6.4, and at this pH, higher concentrations of off odors are formed during storage. Thus, low pH salad dressings are more suitable for storage of ready-to-eat cabbage products in terms of sensory quality, and high temperature is not suitable for cabbage storage, since undesirable aroma compound formation is high, desirable aroma loss occurs quickly, and microbial growth occurs at a very early stage of storage.
AtıfWoS27OpenAlex32İncele - MakaleYalnız künye2015A Study on the Attitudes of Prospective Science Teachers towards the Effects of Mobile Applications and Information Services in Distance Education
Senay, Volkan; Yilmaz, Malik; Senay, Burcu Aydemir; Günes, Aysenur
Today, technology is an essential part of human life and use of the technological devices has rapidly increased. Mobile technology products most often used among the technological devices (smart phones, tablets etc.) offer an opportunity for individuals for easily access to all kinds of information they want without a time and place limit. Mobile technology products previously used as a communication device, today, catch the attention of individuals and/or institutions not only for this purpose, but also making its presence felt in many fields such as trade, education. in the traditional education, also in the distance education, the effect of the information centers and services is important for the information access and sharing of the users to reach to the high level. The presentation of the information resources by the information centers by being digitalized to the users of them is undoubtedly an advantage for the users receiving the distance education. In this study, the description of the opinions of the prospective science teachers concerning the mobile applications and information services in the distance education has been aimed. The sample of the research is composed of Bayburt University and Kastamonu University Primary Science Education Department third class students
- MakaleAçık Erişim2015Scopus SJRQ3An investigation of self-image congruence differences between materialistic and non-materialistic consumers
Başar, Enes Emre; Türk, Bahar; Ünal, Sevtap
This research aims to determine whether there are differences in the self-image congruence between materialistic and non-materialistic consumers towards different product categories (social and private consumption products). The study was carried out on the students of Erzurum Ataturk University using the survey method. Results indicate that there are significant differences in the self-image congruence between materialistic and non-materialistic consumers. Additionally, non-materialistic consumers choose products that reflect their actual selves, whereas materialistic consumers choose products that support their ideal selves.
AtıfScopus4OpenAlex6İncele - MakaleAçık Erişim2015Scopus SJRQ1The effect of starch modification and concentration on steady-state and dynamic rheology of meat emulsions
Genccelep, Huseyin; Saricaoglu, Furkan Turker; Anil, Munir; Agar, Berrin; Turhan, Sadettin
In this study, the effect of starch modification (NPS, native potato starch; AMS, acid modified starch; DMS, dextrinized modified starch; PGS, pre-gelatinized modified starch) and its concentrations (1, 2, 4wt%) on steady-state and dynamic rheological properties of meat emulsions were determined. Water-oil binding capacity and intrinsic viscosity of potato starch increased up to 5.07-0.90g/g, and 14.98mL/g, respectively, after modifying with pre-gelatinization method. The particle size of starches as average mean diameter ranged between 44.19μm and 293.06μm. The maximum solubility was obtained from DMS after heat treatment at 70°C being 48.22%, which means an increase about 3.06-fold in solubility as compared with NPS. The Ostwald-de Waele model was successfully used to describe the flow properties of meat emulsions (R2>0.961). While starch types did not affect the K values of emulsions (p>0.05), starch concentrations did (p<0.01). All studied emulsions exhibited non-Newtonian, pseudoplastic behavior since n values were lower than 1. Emulsion systems were characterized as weak gel-like macromolecular dispersions with storage modulus (G') much greater than loss modulus (G″). A modified Cox-Merz rule was applied by multiplying angular frequency with shift factors (αSF). Frequency dependence of complex modulus (G*) was studied to measure the strength of cross-linking protein network of emulsion systems by calculating a constant order of relaxation function (α) and concentration dependent stiffness parameter (Aα). It was concluded that PGS addition improved rheological properties of meat emulsions due to higher solubility, particle size, intrinsic viscosity, water-oil binding capacity than NPS.
AtıfScopus92WoS77OpenAlex92İncele - MakaleAçık Erişim2015Scopus SJRQ1Comparative study of the magnetic stiffness, levitation and guidance force properties of single and multi seeded YBCOs for different HTS-PMG arrangements
Ozturk, K.; Sahin, E.; Abdioglu, M.; Kabaer, M.; Celik, S.; Yanmaz, E.; Kucukomeroglu, T.
Abstract It is crucial to improve the magnetic levitation, guidance and stiffness performances of the HTS Maglev systems for real-scale applications. In this study, the magnetic levitation force, guidance force and magnetic stiffness values were determined for single and multi-seeded YBCOs on different PMGs in ZFC regime and different cooling heights (CHs) after the magnetic flux distributions simulation of the using PMGs. Implemented study showed that the additional downward PMs make an enhancing contribution on the magnetic levitation force, guidance force and magnetic stiffness of both single and multi-seeded YBCOs. It was also determined that both the force and stiffness ratios of multi-seeded YBCO to single-seeded YBCO increase with increasing CH, indicating that the multi-seeded YBCO has much more interaction domain than single-seeded at higher gaps. It is considered that the results obtained in this study are very useful in technological applications of Maglev and bearing systems, because there is no detailed study on the magnetic stiffness, levitation and guidance force comparison to clarify electromagnetic behavior of single and multi-seeded YBCOs for different HTS-PMG arrangements.
AtıfScopus42WoS39OpenAlex40İncele - MakaleYalnız künye2015Scopus SJRQ3A study on optical, morphological and mechanical properties of Al2O3 ultra-thin films deposited by RF reactive magnetron sputtering
Pat, Suat; Özen, Soner; Şenay, Volkan; Aydoʇmuş, Tuna; Elmas, Saliha; Korkmaz, Şadan; Ekem, Naci; Balbaʇ, M. Zafer
The Al2O3 ultra-thin films with the thicknesses of 30 nm and 35 nm were deposited on glass microscope slides by a radio frequency reactive magnetron sputtering system. The optical, morphological and mechanical properties were investigated as function of the film thickness. The refractive index of the resulting Al2O3 ultra-thin film increased with the increasing thickness. Both the films showed high transparency of > 85% and low reflectivity of < 10% in the visible and near infrared region. A band gap of ∼8.65 eV was obtained for the 30 nm film and ∼7.53 eV for the 35 nm film from an empirical relation between refractive index and band gap. According to the results obtained from the AFM studies, the root mean square surface roughness of the films are 3.67 nm and 3.77 nm for the 30 nm and 35 nm film, respectively. The hardness and Young modulus values decreased with the increasing film thickness.
AtıfScopus8WoS7İncele