Browsing by Author "Akay, Sertan Kemal"
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Item Analytical information on the asphaltenes from a few standard characterization techniques(Taylor & Francis, 2011-01) Peksöz, Ahmet; Akay, Sertan Kemal; Kaya, Yunus; Ovalıoǧlu, Hüseyin; Kaynak, Gökay; Yalçıner, Aytaç; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Anabilim Dalı.; AAG-9772-2021; R-7260-2016; 23100976500; 24801954600; 35181446100; 24460278400; 12042075600; 14055078800The asphaltene has been obtained from asphalt cement with penetration grade 60, which is extracted from crude Libya petroleum. The elemental composition and some structural properties of the asphaltene samples are determined by various methods, such as SEM, infrared spectroscopy, and X-ray analysis. Some experiments are performed on (1)H dynamic nuclear polarization (DNP) in a number of asphaltene suspensions in organic solvents. The frequency dependence of the DNP enhancement under conditions of weak EPR saturation in a low magnetic field is obtained and interpreted as the EPR line shape of some free radicals present in the samples.Item CdS üzerine MgF2 temelli yansıma önleyici ince film kaplamaların üretilmesi ve karakterizasyonu(Bursa Uludağ Üniversitesi, 2022-09-02) Öztatlı, Aybars; Akay, Sertan Kemal; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Fizik Anabilim Dalı.; 0000-0002-5760-8880Optoelektronik uygulamalarda yansıma kayıplarını önlemek için ince film kaplama çalışmalarından yararlanıldığı bilinmektedir. Bu tez çalışmasında, farklı kırılma indislerine sahip malzemeler kullanılarak yansıma önleyici ince film yapıların geliştirilmesi hedeflenmiştir. Bu amaçla, Fiziksel Buhar Biriktirme (PVD) yöntemi kullanılarak, cam alttaşlar üzerine II-IV grubu yarıiletken bileşiği olan Kadmiyum Sülfür (CdS) ve bir toprak alkali metal florürü olan Magnezyum Florür (MgF2) ince filmlerinin büyütülmesi gerçekleştirilmiştir. İnce film yapıların yansıma önleyici özelliklerinin belirlenebilmesi için, cam alttaştan daha yüksek kırılma indisine sahip CdS üzerine, cam alttaştan daha düşük kırılma indisine sahip MgF2 kaplama malzemesi olarak tercih edilmiştir. Farklı kalınlıklarda üretilen çift katmanlı yansıma önleyici ince film kaplamaların yapısal, optik ve morfolojik özellikleri, X-Işınları Kırınımı (XRD), UV-vis spektrofotometre, Enerji Dağılımlı X-Işını Spektroskopisi (EDS) ve Alan Etkili Taramalı Elektron Mikroskobu (FESEM) yardımıyla incelenmiştir. Analizler sonucunda, CdS ince filmler üzerine ikinci katman olarak büyütülen MgF2 ince film yapının optik yansıma kayıplarını görünür bölgede %30'a kadar azalttığı ve buna bağlı olarak geçirgenliği arttırdığı gözlenmiştir. Ayrıca yapılar ayrı ayrı tavlanmış ve tavlamanın optik kayıpları azaltmada etkisinin olup olmadığı araştırılmıştır.Item The characteristics of ZnS/Si heterojunction diode fabricated by thermionic vacuum arc(Elsevier, 2017-07-06) Kaplan, Hüseyin Kaan; Sarsıcı, Serhat; Akay, Sertan Kemal; Ahmetoğlu, Muhittin; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-4144-5837; R-7260-2016; GWV-7916-2022; 57194768599; 57194775738; 24801954600; 16021109400ZnS/p-Si heterojunction diode has been successfully fabricated by depositing the ZnS thin films on p-type Si substrates using thermionic vacuum arc technique (TVA). The structural analysis was performed with X-ray diffraction (XRD) and Atomic force microscopy (AFM). The results revealed that ZnS thin film demonstrates nano-crystalline behavior with very smooth and homogeneous surface properties. The type was determined as n-type and the carrier concentration was found approximately 3.1 +/- 10(17) cm(-3) of the ZnS thin film by means of Hall Effect measurement. The dark current-voltage (I-V) and the capacitance- voltage (C-V) measurements with different frequencies were performed to determine the characteristics of the ZnS/p-Si heterojunction diode at room temperature. I-V results show that the diode has a good rectifying characteristic with excellent rectification ratio. The electrical parameters of the diode have been obtained by using current transport mechanism. It was found that the barrier height calculated from dark I-V measurements is in good agreement with the value obtained from C-V measurements at a frequency of 1.5 MHz. The series resistance and the built in potential of the fabricated diode were calculated as 3.6 k Omega and 0.7 V using Cheung and Cheung's equation and C-V measurement, respectively. The low cost and effective film production method were utilized to fabrication of heterojunction diode and to investigate characteristics.Item Determination of electrical parameters of ZnO/Si heterojunction device fabricated by RF magnetron sputtering(Springer, 2018-09-17) Akay, Sertan Kemal; Sarsıcı, Serhat; Kaplan, Hüseyin Kaan; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-4144-5837; R-7260-2016; GWV-7916-2022; DPZ-0525-2022; 24801954600; 57194775738; 57194768599In the present study, the electrical parameters of the ZnO/Si heterojunction device fabricated via RF magnetron sputtering are examined in detail and the results are compared with literature. Structural and morphological analyses have been done to understand and expound device behavior and results of electrical studies. XRD analysis confirms the crystal formation of ZnO phase with (103) and (111) oriented, while AFM analysis shows that the film surface is homogeneous and the mean roughness is approximately as 2nm. The carrier concentration and conductivity type of ZnO thin film were obtained by Hall Effect measurement as 5.56x10(17)cm(-3), n-type, respectively. The dark current-voltage and capacitance-voltage measurements were carried out to obtain the electrical parameters of the device. From the dark current-voltage measurement the ideality factor, barrier height, and series resistance were estimated as n=2.16, phi(b)=0.71eV, and R-s=92.5. The barrier height was also obtained by the capacitance-voltage measurement handled at room temperature. The results were compared with those obtained from similar or different production methods. Illumination current-voltage measurement was also performed to determine if the fabricated heterojunction device has photovoltaic properties.Item Determination of the parameters for the back-to-back switched Schottky barrier structures(Elsevier, 2010-03) Ahmetoğlu, Muhitdin; Akay, Sertan Kemal; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; R-7260-2016; 15843273600; 24801954600The Cr/n-GaAs/Cr and Ag/p-GaAs/Ag metal-semiconductor-metal (MSM) Schottky contacts have been fabricated by reactive radio frequency (RF) sputtering system. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the devices have been investigated in the temperature range of 80-316 K for the back-to-back switched Schottky barrier contacts. These measurements establish that the room temperature barrier height determined from reverse branch of the current-voltage characteristics is close to the value obtained from capacitance-voltage measurements.Item Development of a polymer based syntactic foam for high temperature applications(Polish Acad Sciences Inst Physics, 2014-02) Fahr, Payam; Shukla, Arun; Yazıcı, Murat; Güneş, Serap; Akay, Sertan Kemal; Uludağ Üniversitesi/Mühendislik Fakültesi/Otomotiv Mühendisliği Bölümü.; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-8720-7594; M-4741-2017; R-7260-2016; 7007162323; 8912603900; 24801954600Syntactic foams are one of the most widely used close cell structured foams. They are used in applications for naval, aeronautical, aerospace, civil, industrial, and automotive engineering due to good acoustical attenuation, excellent strength to weight ratio, vibration isolation, and dielectric properties. These foams are fabricated by incorporation of hollow particles in a matrix material. The most preferred matrix materials are polymers. In this study silicone resin (useful temperature range -53 degrees C to 232 degrees C) was selected as a binder material. Glass bubbles were incorporated into the silicone resin at three different mass percentages (10%, 20%, and 30%). The density of the silicone was reduced more than 50% by 30% glass bubble contribution. The foam mechanical properties were investigated in a room temperature and after heat treatment at 500 C by quasi-static compression experiments. Microstructural transitions by the temperature raises were examined by using scanning electron microscopy pictures. It was observed that the increase of glass bubble percentage in silicone rubber enhanced the energy absorption properties in the heat treated and room temperature specimens. Plateau stress and densification amount were improved under quasi-static compression load by the glass bubble percentage increase. It can be said that developed syntactic foams can be used in heat resistant, low weight and high compression strength exigencies.Item The effect of heat treatments on physical properties of a low carbon steel(Editura Acad Romane, 2009) Akay, Sertan Kemal; Yazıcı, Murat; Avinç, Ahmet; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; 0000-0002-8720-7594; M-4741-2017; R-7260-2016; 24801954600; 7007162323; 6506411792Steel contains 0.055%C was intermediately annealed at 780, 825 and 870 degrees C for 60 minutes followed by water quenching to obtain different microstructures. The effect of heat treatment on the microstructure, crystal structure and electric resistivity of heat treated steels were investigated. It was found that the resulting microstructures had ferrite-plus-martensite known as dual phase steels. The volume fraction of martensite increased with growing annealed temperatures. X-ray diffraction analysis showed that dual phase steel microstructures had body cubic tetragonal martensite crystal structures. The individual diffracting planes of body cubic tetragonal martensite were found as (110) (200) and (211). The lowest resistivity (about 8.48 x 10(-8) Omega.m) was obtained for the dual phase steel samples heal. treated at 780 degrees C. Scanning electron microscopy studies were also discussed for dual phase steel microstructures.Item Electrical, structural and morphological properties of Ni/n-Si contacts(Natl Inst Optoelectronics, 2009-05) Ertürk, Kadir; Özer, Mehmet; Akay, Sertan Kemal; Peksöz, Ahmet; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; R-7260-2016; AAG-9772-2021; 9742545600; 24801954600; 23100976500; 12042075600This paper presents structural, morphological and electrical properties of Ni/n-Si contacts formed by electro-deposition technique. Ni film is deposited on n-type Si (100) substrate using 2 mol/L Nickel Sulphamate, 0.5 mol/L Boric Acid solutions. The morphological properties are investigated by using energy dispersive X-Ray analysis and scanning electron microscopy imaging to perform local distribution of Ni. Electrical measurements have been done at room temperature to investigate the Schottky barrier height.Item Electron-hole interaction in spherical quantum dots of nanoheterostructures(Natl Inst Optoelectronics, 2009-03) Boymatov, P.; Inoyatov, Sh T.; Ahmedov, O. M.; Rahimov, N.; Pulatov, A.; Ahmetoğlu, Muhitdin; Akay, Sertan Kemal; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; R-7260-2016; 16021109400; 24801954600The main states of electron and hole in spherically semiconductor quantum-dot are studied. The wave function of the system is optimized by variation of effective radii of electron and hole orbits. The main state and Coulomb energy as function of quantum-dot radius are calculated.Item Fatigue life behaviour of the dual-phase low carbon steel sheets(Elsevier Science, 2009-04-01) Akay, Sertan Kemal; Yazıcı, Murat; Bayram, Ali; Avinç, Ahmet; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; Uludağ Üniversitesi/Mühendislik Fakültesi/Makina Mühendisliği Bölümü.; 0000-0002-8720-7594; R-7260-2016; M-4741-2017; 24801954600; 7007162323; 7004197848; 6506411792This paper presents the effect of heat treatment on the fatigue life of low carbon steel sheet with dual-phase microstructure. The steel sheets were heat treated with two different procedures; intermediate quenching, intermediate quenching and tempering. The properties of tensile strength, fatigue life, hardness, micro hardness and microstructure were evaluated by the mechanical tests and metallographic analysis, respectively. The results showed that dual-phase steel (DPS) microstructures, composed by ferrite and martensite had higher fully reversed plane bending fatigue strength when compared with as-received steel and tempered martensite (TM) steel. The experimental results showed that fatigue life of the heat-treated steel sheets enhanced with increasing amount of martensite in the microstructure. The highest fatigue strength was observed on the intermediately annealed steel sheets at 870 degrees C. Internal microstructures, fatigue crack initiation and propagation of the heat-treated steel were analyzed by scanning electron microscopy (SEM).Item Giant magnetoimpedance effect in thin zinc oxide coated on co-based (2705 X) amorphous ribbons(IEEE, 2010-02) Tayşioğlu, Aslı Ayten; Kaya, Yunus; Peksöz, Ahmet; Akay, Sertan Kemal; Derebaşı, Naim; İrez, Gazi; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-2546-0022; AAG-9772-2021; AAI-2254-2021; R-7260-2016; 18038658800; 35181446100; 23100976500; 24801954600; 11540936300; 6602755323; 12042075600ZnO film coated Co-based (2705 X) amorphous ribbons are prepared by the successive ionic layer adsorption and reaction technique. The influence of coating on giant magneto-impedance (GMI) has been investigated over a frequency range from 0.1 to 3.5 MHz and under a static magnetic field between -8 and +8 kA/m. The highest GMI ratio of 15.63% was obtained in the coated Co-based amorphous ribbons which is 80% higher than the sample without coating. The results indicate that the surface coating process plays an important role in the GMI effect.Publication Investigation of the structural, magnetic, and cooling performance of AlFe thin film and AlFeGd nanometric giant magnetocaloric thin films(Springer, 2021-02-02) Pat, Suat; Bayer, Özgür; Akay, Sertan Kemal; Mohammadigharehbagh, Reza; Kaya, Metin; AKAY, SERTAN KEMAL; Mohammadigharehbagh, Reza; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; 0000-0002-0333-487X; R-7260-2016; X-5375-2018Giant magnetocaloric thin films are promising materials for new generation energy-efficient cooling systems. To investigate the cooling performance of AlFe and AlFeGd alloys, thin films have been deposited onto a glass substrate by thermionic vacuum arc (TVA) deposition system. TVA is a physical vapor deposition technology; it works in high vacuum and low-temperature conditions. AlFe and AlFeGd thin films are of significant importance for giant magnetocaloric materials. The surface and magnetic properties of a magnetic material are strongly dependent on the deposition process. In this paper, the structural, magnetic, and cooling performances of AlFe alloys with and without the Gd element have been investigated. When the Gd elements are added to AlFe alloys, the size of crystallite and the surface morphology of the giant nanometric magnetocaloric thin films are altered. The size of crystallite decreases to a lower value due to the Gd element added. According to the results of the elemental analysis, the elemental ratios of the AlFe and AlFeGd thin films were measured as (87:13) and (84:4:12), respectively, which are different from the ones reported previously. Magnetic cooling performance and magnetization strongly depend on these ratios. The mean values of crystallite size for the AlFe thin film and AlFeGd nanometric giant magnetocaloric thin film were measured as 50 nm and 12 nm, respectively. Following the Curie temperature of AlFeGd thin film, and the temperature difference it produces in the studied magnetic fields, 60 successive units of this material are assumed to form a magnetic refrigeration cycle. The coefficient of performance of this cycle is calculated to be 2.084-nearly two times better than the suggested cascade vapor-compression cycles in the same temperature range. This fact alongside the solid-state and environmentally friendly attributes of magnetic refrigeration cycles makes the AlFeGd thin films a strong candidate for accomplishing an efficient refrigeration system.Item An investigation on surface and electrical properties of electrical discharge machined AISI D2 tool steel(Polish Acad Sciences Inst Physics, 2014-02) Durmuş, Ali; Bayram, Ali; Güneş, Serap; Akay, Sertan Kemal; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; Uludağ Üniversitesi/Mühendislik Fakültesi/Makina Mühendisliği Bölümü.; R-7260-2016; 55964532400; 7004197848; 8912603900; 24801954600The effects of pulse-on duration and finishing operation on the surface roughness and electrical resistivity of AISI D2 tool steel machined by the electrical discharge machining process are investigated. Experimental results indicate that surface roughness increased depending on the pulse-on duration. However, after the specific value, surface roughness is decreased. It can be seen that there are no notable effects of the pulse-on duration on the electrical resistivity, but the resistivity values are affected by the heat treatment and the finishing operation. Also, light microscopy and scanning electron microscopy have been used to study the characteristics of the surfaces.Item Kalkojenit temelli nanokompozit ince filmlerin üretilmesi ve optoelektronik cihaz uygulaması(Bursa Uludağ Üniversitesi, 2022-10-18) Kaplan, Hüseyin Kaan; Akay, Sertan Kemal; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Fizik Anabilim Dalı.; 0000-0002-4144-5837Günümüzde, ITO, FTO gibi n-tipi şeffaf iletken materyaller ticari seviye birçok optoelektronik cihaz uygulamasında kullanılabilecek gelişimi yakalamışken, performansı yeterince yüksek p-tipi şeffaf iletken ince-film materyaller henüz geliştirilememiştir. Bu nedenle, bu tez çalışmasında termal buharlaştırma yöntemi kullanılarak, nanokompozit yapılı (CuS)x:(ZnS)1-x p-tipi şeffaf iletken ince-filmlerin üretilmesi üzerine çalışmalar yürütülmüştür. Bakır sülfür ve çinko sülfür mikro-tozlarının belirli oranda karıştırılmasıyla hazırlanan pellet kaynaklardan termal buharlaştırma yöntemiyle Si ve cam alttaşlar üzerine farklı x değerleri için (CuS)x:(ZnS)1-x ince-filmler büyütülmüştür. Üretilen bu numunelerin X-ışını kırınımı analiziyle iki bileşiğe de ait nano-kristallerinden oluştuğu ve kristal tane boyutlarının (CuS)0,49:(ZnS)0,51 numunesinde 30 ile 86 nm aralığında değiştiği belirlenmiştir. FESEM analiziyle alınan yüzey ve kesit görüntülerinden hem yüzeyin oldukça düzgün ve homojen olduğu hem de kalınlığın üretim esnasında ölçülen değerler (50 nm) ile tutarlı olduğu belirlendi. Ayrıca, FESEM incelemesi sırasında yapılan EDS analiziyle de elementel kompozisyonları belirlendi. Moleküler yapıyı ve bileşen elementlerin iyonik durumlarının incelenmesi için XPS analizi yapıldı, elde edilen bulgularla XRD analizinden elde edilen bulgular doğrulandı. UV-Vis spektrofotometre ölçümleri uygulanarak filmlerin 550 nm dalgaboyundaki optik geçirgenliklerinin %65 ile %83 arasında değiştiği, yani oldukça şeffaf oldukları belirlendi ve enerji bant aralığı (Eg) değerleri Tauc metodu kullanılarak hesaplandı. Hall Etkisi ölçümleriyle elektriksel parametreler belirlendi. (CuS)0,49:(ZnS)0,51 numunesinde 5,24×1021 cm-3 hol konsantrasyonu, 1,69 cm2·V-1·s-1’lik mobilite değerleri ve 1420 S/cm gibi çok yüksek bir p-tipi iletkenlik değeri ölçüldü. Böylesine yüksek hol konsantrasyonuna sahip olmasının nedeni moleküler analiziyle açıklandı. Tüm bunlara ek olarak nanokompozit yapılı (CuS)x:(ZnS)1-x ince-filmlerden Si tabanlı üç tane fotodiyot da üretildi. Spektral fotoakım ölçümleriyle yapılan analizlerle çoğu ticari seviye fotodiyotu aşan foto-duyarlılık ve dedekte edebilme kabiliyetine sırasıyla, 11,4 A/W ve 3,2×1013 Jones değerleriyle sahip olduğu belirlendi. Bununla beraber, yüzde yüzü aşan az rastlanır EQE (kuantum verimi) değeri %2,85×103 (p-CZS49/n-Si için) elde edildi.Item Magnetic properties of poly (divinylbenzene, ethylene glycol dimethacrylate and vinyl alcohol) containing barium ferrite nanoparticles(Polish Acad Sciences Inst Physics, 2014-02) Güneş, Serap; Akay, Sertan Kemal; Kara, Ali; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; 0000-0003-2457-6314; R-7260-2016; AAG-6271-2019; 8912603900; 24801954600; 7102824859Three different kinds of polymer films, poly (divinylbenzene), poly (ethylene glycol dimethacrylate) and poly (vinyl alcohol), containing M-type hexagonal barium ferrites (BaFe12O19) were synthesized on glass substrates by using surface polymerization method. The structural properties were characterized by X-ray diffraction and atomic force microscopy. X-ray diffraction patterns show that polymer films have a polycrystalline structure. The magnetic measurement of polymer films were examined at room temperature using vibrating sample magnetometer and magnetic force microscopy, respectively. The magnetic measurements indicate that P(VA)-BF films exhibit higher saturation magnetization and coercive field than P(EGDMA)-BF and P(DV13)-BF films.Item Magnetic responses of divinylbenzene-Fe3O4 composite film deposited by free radical polymerization method(Springer, 2018-03) Akay, Sertan Kemal; Peksoz, Ahmet; Kara, Ali; Uludağ Üniversitesi/Fen - Edebiyat Fakültesi/Fizik Bölümü.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0003-2457-6314; R-7260-2016; AAG-9772-2021; AAG-6271-2019; 24801954600; 23100976500; 7102824859The study reports some novel information on both production and characterization for the poly [DVB/Fe3O4] composite film deposited by free radical polymerization method. The composite film consists of a combination of organic phase and magnetite nanoparticles. The magnetization behavior of the poly [DVB/Fe3O4] composite film was analyzed with both vibrating sample magnetometers (VSM) and a technique of electron spin resonance (ESR). It was found that the ESR study performed at room temperature showed the poly [DVB/Fe3O4] composite film had strong transition of g (eff) similar to 2.5 (254 mT) due to the Fe3+ S-state ions. This g (eff) value indicated that the composite film behavior was near superparamagnetism. The VSM results also supported the ESR results.Item Otomotiv endüstrisinde kullanılan çift fazlı çeliklerin fiziksel özelliklerinin araştırılması(Uludağ Üniversitesi, 2005-12-16) Akay, Sertan Kemal; Avinç, Ahmet; Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Fizik Anabilim Dalı.Bu araştırmada, çift fazlı çelik üretmek için % 0.055 C’ lu çelik kullanılmıştır. Standartlara göre hazırlanmış yorulma deney örnekleri iki farklı ısıl işleme tabi tutulmuştur. I. grup ısıl işlemde, normalize edilmiş örnekler ostenit bölgesinde 940°C sıcaklıkta 45 dakika tavlanarak suda soğutulmuştur. Daha sonra aynı örnekler, ferrit + ostenit bölgesinde 780°C, 825°C ve 870°C sıcaklıklarında 60 dakika tavlanarak suda soğutulmuştur. II. grup ısıl işlemde, I. grup ısıl işlemle üretilen çift fazlı çelikler 400°C’ de 2 saat tavlanarak ısı verme işlemi uygulanarak havada soğutma uygulanmıştır. Farklı ısıl işlemlerle üretilen değişik mikro yapılı çift fazlı çelik örneklere sabit hızda çekme testleri uygulanarak mekanik özellikleri incelenmiştir. Isıl işlem sonrası, çift fazlı çeliklerin kristal yapısı ve bozunumları x ışını kırınımı deneyi kullanılarak ve bu çeliklerin elektrik özdirenç ölçümleri de dört nokta elektrot yöntemi ile elde edilmiştir. Bu örneklere düşük frekanslarda (50 Hz-100 Hz) mıknatıslama uygulanarak manyetik özellikleri (B – H değişimleri) incelenmiştir. Değişik martenzit miktarına sahip çift fazlı çelik örneklerin yorulma ömürleri yorulma test cihazı ile belirlenmiştir. Çift fazlı çeliklerin elde edilen yorulma değerleri ferrit + perlit mikro yapısına sahip çeliklere göre iyileşme sağlandığı sonucuna varılmıştır. Çift fazlı çeliklerin yorulma kırılma yüzeyleri elektron mikroskobu ile incelenerek, çatlak başlangıç ve ilerleme mekanizmaları incelenmiştir.Publication P-type transparent Cu2S thin film grown by thermionic vacuum arc for optoelectronic applications(Elsevier, 2021-01-01) Kaplan, Hüseyin Kaan; Akay, Sertan Kemal; Pat, Suat; Henini, Mohamed; KAPLAN, HÜSEYİN KAAN; AKAY, SERTAN KEMAL; 0000-0001-9414-8492; R-7260-2016; GWV-7916-2022In this study, we have used a new single-step method for producing Cu2S thin films, which have good transparency in the visible range and high hole conductivity properties suitable for a wide range of optoelectronic device applications. Cu2S thin films are deposited by the Thermionic Vacuum Arc method, which is capable of very high deposition rates with high uniformity. The structural properties were determined by XRD analysis, and the morphological features were examined by AFM and SEM techniques. From XRD studies, the thin films were found to have a nano-crystalline form. The morphology images showed that the thin films have very low surface roughness. The bandgap of the film was calculated. The electrical properties of the films such as resistivity, majority carrier, and concentration were determined by Hall Effect measurements. In addition, the figure of merit value was calculated for p-type Cu2S transparent conducting thin films using the Haacke's formula.Item Photoelectrical properties of fabricated ZnS/Si heterojunction device using thermionic vacuum arc method(Elsevier, 2018-05-24) Kaplan, H. K.; Akay, Sertan Kemal; Ahmetoğlu, Muhitdin; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-4144-5837; GWV-7916-2022; R-7260-2016; 57194768599; 24801954600; 16021109400ZnS thin films have been successfully deposited with the same production parameters using thermionic vacuum arc technique on glass and silicon substrates. UV-Vis absorbance spectra and photoluminescence measurements were performed for the optical characterization of ZnS/glass thin film and ZnS/p-Si heterojunction device, respectively. The optical band gap is found approximately 3.78 eV. Further, electrical parameters of the device were determined for the current-voltage (I-V) measurements in dark and under illumination conditions. The open-circuit voltage and the short-circuit current values have been obtained related to illumination I-V measurements. Also, we have utilized photocurrent measurements to investigate the wavelength dependent to photosensitivity of the ZnS/p-Si heterojunction device.Item The physical properties of CZTS absorber layer for solar cell application(Bursa Uludağ Üniversitesi, 2021-01-26) Sarsıcı, Serhat; Kaplan, Hüseyin Kaan; Olkun, Ali; Mohammadigharehbagh, Reza; Akay, Sertan Kemal; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-1288-0431; 0000-0002-4144-5837; 0000-0003-0061-0573; 0000-0002-0333-487X; 0000-0002-7597-1528In this research, the Kesterite structure CZTS absorber layer was deposited on the glass substrate using a vacuum thermal evaporation technique. The morphological, electrical, structural, and optical properties of the produced films were examined utilizing Atomic Force Microscopy, Hall Effect Measurement system, Raman spectroscopy, and UV-Vis spectrophotometer measurements. The Raman analysis confirms the domination of Kesterite phase CZTS on the glass substrate, while secondary and ternary phases are also detected. According to the optical results, the optical bandgap value was calculated as 1.46 eV. The film's electric resistivity was measured as about 67 and 331 Ω.cm at 1 and 100 nA currents, respectively. The carrier concentration values were similarly calculated at 10¹⁵ cm-³for 1 and 100 nA, respectively. Regarding the surface analysis, the RMS roughness value of the film is measured as approximately 5 nm. The RMS roughness and optical bandgap values illustrate the excellent morphological distribution and optical properties and proved that the used deposition technique is one of the best methods.