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A new Schottky barrier diode of Al/Coronene/n-GaAs/In was successfully prepared using spincoating method. The interface state and electrical properties of Al/Coronene/n-GaAs Schottky barrier diode have been studied by current– voltage (I–V) data in dark and light. The key diode parameters such as ideality factor, Schottky barrier height, rectification ratio, series and shunt resistances were evaluated from I–V data. The effective forward conduction mechanisms were determined as the thermionic emission at low voltage. Results obtained at room temperature (300 K) showed highly rectifying devices under dark and light. The barrier height ( B ) of the diode was obtained as 0.901 eV and 0.842 eV under dark and light, respectively. The ideality factor (n) of the diode was calculated to be 1.49 and 1.82 under dark and light, respectively. The values of series resistance ( ) Rs obtained from Cheung-Cheung technique were determined to be 18  and 16  under dark and light, respectively. The interface states density (Nss) of the Shottky device exhibits an exponential decrease with bias from 5.31x1010 eV-1 cm-2 and 7.24x1010 eV-1 cm-2 at (Ec-0.338) eV to 1.84x1010 eV-1 cm-2 and 2.17x1010 eV-1 cm-2 at (Ec-0.640) eV under dark and light, respectively.

In this study one year data of grid connected system with thin film a-Sitechnologies in Batman province which has 2.16 kWp power and their moduleperformance comparisons were evaluated according to external parameters. Thedata set covers from January until December 2016. The thin film a-Si PV systemsupplied 2.631 MWh energy to the grid during 2016. The final yield (Yf) this PVsystem ranged from 1.13 to 4.89 kWh/kWp/day and the performance ratio (PO)ranged from 53 to 78%. The effect of ambient and module temperatures on thesystem performance is calculated in the range 6% to 9%. It has also beendetermined that other parts of PV system affect system performance at variousratios., Bu çalışmada Batmanilinde ince film a-Si teknolojisine sahip 2.16 kWp güce sahip şebeke bağlantılısistemin bir yıllık elektrik enerjisi üretim verileri alınmış ve modüllerinperformansı dış parametrelerde göz önüne alınarak değerlendirilmiştir. Sistemölçümleri Ocak ayından Aralık ayına kadar tüm 2016 yılını kapsamaktadır. İncefilm a-Si PV sistemden 2016 yılı süresince şebekeye 2.631 MWh enerjisağlanmıştır. Sistemin nihai verimi (Yf) 1.13 den 4.89kWh/KWp/gün’e, performans oranı da (PO) %53 ile %78 arasında değişmektedir.Ortam ve buna bağlı olarak modül sıcaklıklarının sistem performansına etkisinin%6 - %9 arasında olduğu hesaplanmıştır. Ayrıca diğer sistem bölümlerinin desistem performansı üzerinde değişen oranlarda etkili olduğu belirlenmiştir.&nbsp

0000-0003-0716-9194 WOS: 000418815100022 In this study, Al/HfO2/p-Si (MIS) structures were prepared by using the sol-gel method for three different annealing temperatures. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of these structures were investigated by taking into consideration the effect of the interfacial insulator layer and surface states (N-ss) at room temperature. All of the structures showed non-ideal I-V behaviour with ideality factor (n) in the range between 2.35 and 4.42 owing to interfacial insulator layer and surface states. The values of N-ss and barrier height (phi(b)) for three samples were calculated. The values of n and N-ss ascend with increasing the insulator layer thickness (delta) while the values of phi(b) decreases.

High-energy radiation penetrates the metal-semiconductor (MS) interface and causes damage deep below the interface. Low-energy radiation causes severe lattice damage in the form of vacancies, interstitials and defect complexes at the near interface of the device. The one kind of the radiation is electron beam which is accelerated. Mills was the first to recognize that electrons with energy of 1 MeV would possess enough energy to displace an atom from its lattice position. This observation has led to the increased use of electron accelerators in radiation damage studies. This use has been motivated by two important facts. First, electron bombardment experiments permit the determination of the energy required to remove an atom from its initial position. This is done by increasing the energy of the electrons until an observable change in a radiation-sensitive property is seen. The second important basis for the use electrons lie in the fact that as long as the energy of the electrons is close to the displacement threshold, it is presumed, that only single Frenkel pairs are formed. Thus, many radiation-induced phenomena can be analyzed in terms of a single vacancy and/or interstitial atom, and one avoids the complication attendant upon the generation of complex damage regions presumed to occur in heavy-charged particle irradiation. In the present paper, a lead/rhodamine-101(Rh101)/p-Si metal/organic interlayer/ semi-conductor diode was fabricated and the effect of 6 MeV-electron irradiation on the electrical characteristics of the diode structure was investigated. It was seen that after electron irradiation the barrier height values, the series resistance values and ideality factors increased. Furthermore, it was seen that the capacitance values increased after electron irradiation. This was attributed to the change in dielectric constant at the interface and/or to decrease in the net ionized dopant concentration and the interface states. The degradation of the diode properties may be due to the introduction of electron irradiationinduced interfacial defects via displacement damage.

The radiation response of metal-semiconductor (MS) contacts has been found to alter significantly when the structures are exposed to pre-irradiation processes at determined doses. Radiation doses greater than a kilogray exposure may cause strong changes on the electrical characteristics of MS structures. It has been also shown that the particle or gamma irradiations induce defects in the band gap which affects the free carrier concentration and leads to an increase and decrease of barrier height in p-type and n-type semiconductors, respectively. The knowledge of the influence of radiation damage on the Schottky barrier diodes (SBDs) performance is a fundamental field of research, having technological relevance for many applications in the semiconductor electronic devices. Hence, it is very much essential to evaluate the effect of irradiation and identify the degradation mechanism to understand the failure mechanisms. In this work, we have investigated the electrical parameters of the Sn/p-Si Schottky barrier diodes by using I-V and C-V characteristics under γ-irradiation at room temperature. The basic diode parameters such as ideality factor, barrier height, series resistance and reverse saturation current were extracted from electrical measurements as a function of the irradiation dose. The results indicated that γ-irradiation induced an increase in the effective Schottky barrier height extracted from both I-V and C-V measurements. Also, it was seen that ideality factor increased with the increasing γ-irradiation doses. We have also observed that the reverse bias current of the Sn/Si contact exceedingly decreased with increasing irradiation dose with low energy (60 keV). The basic results as related to the gamma irradiation have been indicated that this device may have applications as radiation sensors in order to detect the low energy gamma radiation.

The aim of the study is to develop a more economic and easier method which has lower temperature in obtaining ZrO2 thin films contrary to the literature. In this study, we produced thin ZrO2 films on amorphous glass substrates through the wet chemical method by using different chemicals with the same starting reactive. X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectroscopy measurements of the produced films were conducted and the results were compared. The best method has been identified at the end of the analysis and it has been observed that the features of the films produced with this method have given better results than both the films produced by using different reagents and the films produced in literature.

In this work, we have studied the electrical characteristics of the Al/CR/p-Si MIS Schottky structures formed by coating of the organic material directly on p-Si substrate. It has been seen that the CR thin film on the p-Si substrate has indicated a good rectifying behavior. The barrier height and the ideality factor of the device have been calculated from the I-V characteristic. We have also studied the suitability and possibility of the MIS diodes for use in barrier modification of Si MS diodes. In addition, we have compared the parameters of the Al/CR/p-Si MIS Schottky diodes with those of conventional Al/p-Si MS diodes. We have observed that the b value of 0.77 eV obtained for the Al/CR/p-Si device was significantly larger than BH value of the conventional Al/p-Si MS contact. Thus, the modification of the interfacial potential barrier for metal/Si diodes has been achieved by using the CR organic interlayer. This was attributed to the fact that the CR interlayer increased the effective b by influencing the space charge region of Si. The interface-state density of the MIS diode was found to vary from 1.24×1013 eV-1 cm-2 to 2.44×1012 eV-1 cm-2.

The performance of a photovoltaic (PV) system depends on both the module technology and also on the outdoor conditions. The impact of solar radiation, ambient and module temperature, humidity, dust and ventilation can strongly affect energy production of the PV system. In this study, three 2.2 kW grid-connected PV generation systems under the outdoor conditions are analyzed in Batman (Turkey). The types of modules examined in this study are: monocrystalline silicon, polycrystalline silicon and amorphous silicon. The monthly and annual performance ratios have been calculated for the three modules and a comparison is presented here. Optimization potentials of Batman are also discussed.

Solar energy is one of the most widely used renewable energy resources in the world. A drawback, common to the photovoltaic systems (PV) is their unpredictable nature and their output cannot be accurately predicted, because, these systems are dependent on climatic conditions. Solar radiation data are the best source of information for proper design of PV systems. In this study; hourly tilted surface solar radiation is measured at different slope angles in Batman (Turkey). Selected models were compared on the basis of the statistical error tests; mean square errors (MSE), mean absolute errors (MAE) and root mean square errors (RMSE) and mean absolute percentage error (MAPE). Besides, a new equation was developed to calculate monthly average daily global solar radiation in Batman.

In this work, it has been investigated current-voltage (I-V) andcapacitance-voltage-frequency (C-V-f) characteristics of the Al/SafranineT(ST)/n-Si structure. The values of the ideality factor, series resistance and barrier height calculated by using different methods were compared. It was seen that there was an agreement with each other. Also, it was seen that the barrier height value for our device was higher than one value of 0.50 eV of conventional Al/n-Si Schottky contact. The change in the barrier height value of the device was ascribed to ST thin layer modifying the effective barrier height by influencing the space charge region of the Si inorganic semiconductor. The downward concave curvature of the forward bias current-voltage characteristics at sufficiently large voltages have been attributed to the effect of series resistance. Thus, the concavity of the forward bias current-voltage characteristics increases with increasing series resistance value. It has been seen that the values of capacitance are almost independent to a certain value of frequency, after this value, the capacitance decreases with increasing frequency. The higher values of capacitance at low frequencies have been attributed to the excess capacitance resulting from the interface states in equilibrium with the n-Silicon that could follow the alternating current signal.

In this study; temperature-dependent current-voltage measurements are used to determine the dominant currenttransport mechanism of ZnO/CdS/Cu(In,Ga)(S,Se)2 heterojunction solar cells. The dominant current-transport mechanism is mainly driven by changes in the Cu and S-stoichiometry. Whereas Cu and S rich devices are dominated by recombination at the CdS/absorber interface, bulk recombination in Cu and S poor devices irrespective of the band gab energy of the absorber.

We have studied the I-V, C-V and C-f characteristics of the Aniline Green (AG)/n-type Si structure. In organic/inorganic semiconductor contact applications, in order to keep the technological difficulties and unknowns to a minimum, silicon is generally chosen as the substrate semiconducting material. In this structure, deposition of organic materials on the inorganic semiconductor can generate large number of interface states at the semiconductor surface that strongly influence the electrical properties of the AG/n-Si structure. The values of the ideality factor, series resistance and barrier height obtained from two methods were compared, and it was seen that there was an agreement with each other. The downward concave curvature of the forward bias current-voltage characteristics at sufficiently large voltages is caused by the presence of the effect of series resistance. Thus, the concavity of the forward bias current-voltage characteristics increases with the increasing series resistance value. The high resistance values have given the high ideality factors. Also, the higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the nSi that can follow the ac signal.

The present study aimed to examine the current density-voltage (J-V) characteristics of Al/HfO2/p-Si (MOS) structure at temperatures ranging between 100 and 320 K and to determine the structure’s current transport mechanism. The HfO2 film was coated on a single side of the p-Si (111) crystal using the spin coating method. The J-V measurements of the obtained structure at the temperatures between 100 and 320 K revealed that the current transport mechanism in the structure was compatible with the Schottky emission theory. The Schottky emission theory was also used to calculate the structure’s Schottky barrier heights ( 𝜙 𝐵 ), dielectric constants ( 𝜀 𝑟 ) and refractive index values of the thin films at each temperature value. The dielectric constant and refractive index values were observed to decrease at decreasing temperatures. The capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of Al/HfO2/p-Si (MOS) structure was measured in the temperature range of 100–320 K. The values of measured C and G/ω decrease in accumulation and depletion regions with decreasing temperature due to localized 𝑁 𝑠 𝑠 at Si/HfO2 interface.

Bu çalışmanın amacı yalıtkan tabakası sol-jel yöntemiyle hazırlanmış Al/TiO2/p-Si (MIS) yapılarında yüzey şartlarının elektriksel belirtkenler üzerindeki etkisinin araştırılmasıdır. Öncelikli olarak cam yüzeyine farklı sıcaklıklarda hazırlanmış TiO2 ince filmlerin optiksel, yapısal ve elektriksel özellikleri incelenerek hazırlama şartları hakkında bilgi edinilmiştir. Bu özellikleri incelemek üzere FTIR spektrumlarından, UV-VIS spektrumlarından, XRD desenlerinden, AFM görüntülerinden ve akım-gerilim (I-V) ölçümlerinden yararlanılmıştır. Daha sonra aynı şartlar altında hazırlanmış TiO2 ince filmleri p-tipi silisyum alt tabakalar üzerine kaplanarak, bu yapılardan Al/TiO2/p-Si metal/yalıtkan/yarıiletken (MIS) yapıları elde edilmiştir. Elde edilen Al/TiO2/p-Si (MIS) yapılarının oda sıcaklığında I-V ve kapasite-gerilim (C-V) ölçümleri gerçekleştirilmiş ve yapıların temel elektriksel belirtkenleri tayin edilmiştir. Bu temel elektriksel belirtkenler yardımıyla yapıların ara yüzey enerji durumlarının değişimi tespit edilmiştir. Elde edilen bu veriler yardımıyla en iyi belirtkenlere sahip Al/TiO2/p-Si (MIS) yapısı belirlenmiştir. Son olarak da belirlenmiş olan Al/TiO2/p-Si (MIS) yapısının sıcaklığa bağımlı I-V ölçümleri yapılmıştır ve yapının akım-iletim kuramı hakkında bilgi edinilmiştir. The present study aims to investigate the effect of interface states on electrical parameters in Al/TiO2/p-Si (MIS) structures whose insulator layers were prepared by the sol-gel method. Firstly, optical, structural, and electrical properties of TiO2 thin films prepared on glass at different temperatures were examined to obtain information about their preparation conditions. In order to examine these conditions, their FT-IR spectra, UV-VIS spectra, XRD patterns, AFM images, and current-voltage (I-V) measurements were used. TiO2 thin films prepared under the same conditions were then coated on p-type silicium wafers and from these structures, Al/TiO2/p-Si metal/insulator/semi-conductor (MIS) structures were produced. The I-V and capacitance-voltage (C-V) measurements of the obtained Al/TiO2/p-Si (MIS) structures were then performed at room temperature and the main electrical characteristics of the structures were determined. Using these main electrical characteristics, energy distribution profile of interface states of the structures was determined. Through the obtained data, the Al/TiO2/p-Si (MIS) structure with the best characteristics was selected. Finally, temperature-dependent I-V measurements were conducted for the selected Al/TiO2/p-Si (MIS) structure and information was obtained on the current transport theory of the structure. 105

Bu çalışmada toplu buharlaştırma tekniğiyle büyütülmüş olan CuIn(S,Se)2tabanlı heteroeklem aygıtların elektronik özellikleri iki grupta ele alınarakincelenmiştir. Birinci grup, Cu/In oranı sabit S/(S+Se) oranı değişken; ikinci grup iseS/(S+Se) oranı sabit Cu/In oranı değişken örneklerden oluşmaktadır. Parametreleristokiometriye bağlı güneş pillerinin akım-gerilim karakteristikleri 250C sıcaklıkta100mW/cm2'lik ışınım altında ölçülmüştür. Soğurucu tabakasındaki bakır oranı sabitörneklerde, bulunan Voc ve doluluk faktörü değerlerinin S/(S+Se) oranına göre azduyarlı iken Jsc değerlerinin azaldığı belirlenmiştir. Bununla birlikte S/(S+Se) oranısabit Cu/In oranı değişimine göre Voc ve doluluk faktörü değerlerinin arttığı ve Jscdeğerlerinin az duyarlı olduğu saptanmıştır.Eklem kapasitansı ölçümlerinde, tabakadaki Cu/In oranı sabit iken tuzakseviyelerinin aktivasyon enerji değerlerinin tümünün benzer özellik gösterdiği veyaklaşık 110meV civarında olduğu saptanmıştır. Cu/In oranı azalırken ise bir öncekituzak seviyelerinin 229meV ve 246meV olduğu saptanmıştır.Heteroeklemlerin yasak enerji aralığı değerleri kuantum verimliliği (QE)spektrali ile belirlenmiş olup soğurucu tabakanın yasak enerji aralığı değerlerinin1.0eV ile 1.3eV arasında olduğu bulunmuştur. Güneş pillerinin sıcaklığa bağımlıakım-gerilim ölçümlerinde ise baskın olan akım-iletim mekanizmaları belirlenmeyeçalışılmıştır. Tüm güneş pillerinin aktivasyon enerji değerlerinin yasak enerji aralığıdeğerlerinden daha küçük değerde olduğu bulunmuş ve baskın olan akım iletimmekanizmasının ara yüzeyde yeniden birleşme mekanizması olduğu belirlenmiştir. This work attempts to analyse the data on electronic properties of two groupsof CuIn(S,Se)2 based heterojunction devices deposited by co-evaporation technique.In the first group of samples; Cu/In ratio was kept constant and S/(S+Se) ratio waschanged, in the second group S/(S+Se) ratio was maintained the same while theCu/In ratio was altered. In an attempt to correlate solar cell parameters to thestoichiometry, current-voltage characteristics of these cells were measured under anillumination of 100mW/cm2 at 250C. For the constant copper content in the absorberlayers, both Voc and fill factor values are found to be only slightly sensitive to theS/(S+Se) ratios, whereas Jsc values decreased with increasing the S/(S+Se) ratios.However for the constant S/(S+Se) content, as the Cu/In ratio increases Voc and fillfactor values were observed to be improved significantly but Jsc exhibits only slightchange.From the junction capacitance measurements, for the constant Cu/In contentin the layers, all the activation energy values of the trap levels determined exhibitedsimilar values around 110meV. As the Cu/In ratio is reduced, in addition to theformer level, trap levels at about 229meV and 246meV were identified.The dependence of the band gap energy, Eg on the composition wasdetermined from the evaluation of quantum efficiency (QE) spectra of theheterojunctions. The values of the band gap energy for the absorber layers werefound to change between 1.0eV and 1.3eV. Temperature dependent current-voltagemeasurements were used to determine the dominant current mechanism in these solarcells. Basically for all types of the cells, the current was found to mainly bedominated by the recombination at the hetero-interface, with activation energiessmaller than the values of the band gap of the absorber material. 105

Bu çalışmada Trimetilolpropane Triakrilat (TMPTA) Polimer arayüze sahip Metal-Polimer-Yarıiletken (MPS) aygıtların oda sıcaklığında akım - gerilim (I-V) ve kapasite-gerilim (C-V) analizleri incelenmiştir. Al/TMPTA/p-Si (MPS) yapısının karanlık altındaki akım-gerilim (I-V) ölçümleri gerçekleştirilerek; doğrultma oranı (RR), idealite faktörü (n), engel yüksekliği (ϕB) ve seri direnç (Rs) gibi aygıt parametreleri belirlenmiştir. Ayrıca kapasite-gerilim (C-V) ve iletkenlik-gerilim (G-V) ölçümleri ile diğer elektriksel parametreler belirlenmiştir. Sonuçlar literatür ile karşılaştırılmış, TMPTA fotopolimer organik arayüzey tabakasının MPS aygıtlarının fabrikasyonu için iyi bir aday olduğu görülmüştür., In this study, current-voltage (I-V) and capacitance-voltage (C-V) analyzes of Metal-Polymer-Semiconductor (MPS) devices with Trimethylolpropane Triacrylate (TMPTA) Polymer interface were investigated at room temperature. By performing current-voltage (I-V) measurements of the Al/TMPTA/p-Si (MPS) structure under dark; Device parameters such as rectification ratio (RR), ideality factor (n), barrier height (ϕB) and series resistance (Rs) were determined. In addition, capacitance-voltage (C-V) and conductivity-voltage (G-V) measurements and other electrical parameters were determined. The results were compared with the literature and it was seen that the TMPTA photopolymer organic interfacial layer is a good candidate for fabrication of MPS devices.

Bu tez çalışmasında silikon tabanlı BPW41N (PIN) fotodiyotunun elektriksel karakterizasyonu gerçekleştirilerek, elektriksel parametreler belirlenmiş ve bu parametreler aracılığı ile baskın olan akım iletim mekanizması hakkında bilgi edilmeye çalışılmıştır. 80-300K sıcaklıkları arasında akım-gerilim (I-V) ölçümlerinden PIN foto diyotumuzun uygulanan gerilim değeri ile seri direnç etkisine bağlı olarak sapma meydana geldiği görülmüştür. Baskın akım-iletim mekanizmasına göre elektriksel belirtkenler tayin edilmiştir. Ayrıca Norde ve Cheung metodundan yararlanarak aygıtımızın seri direnci belirlenmeye çalışılmıştır. Oda sıcaklığında Norde fonksiyonu ile seri direnç ve engel yüksekliği 147 Ω ve 0,881 eV ve Cheung metodu ile de seri direnç 2,77 ve 2,076 Ω, engel yüksekliği 2,083 Ω, ve 0,654 eV olarak hesaplanmıştır. Bu farklılıklar akım-iletim mekanizması ve yöntemlere bağlı olarak yorumlanmıştır., In this thesis, the electrical characterization of the silicon-based BPW41N (PIN) photodiode was performed and its electrical parameters were determined and information about the dominant current conduction mechanism was tried to be obtained through these parameters. From the current-voltage (I-V) measurements between 80-300K temperatures, it was observed that there was a deviation due to the series resistance effect with the applied voltage value of our PIN photo diode. The electrical parameters were determined according to the dominant current conduction mechanism. In addition, the series resistance of our device was tried to be determined by using Norde and Cheung methods. At room temperature, the series resistance and barrier height were calculated as 147 Ω and 0.881 eV with the Norde function, and the series resistance was calculated as 2.77 and 2.076 Ω, the barrier height was 2.083 Ω, and 0.654 eV with the Cheung method. These differences have been interpreted depending on the current-conduction mechanism and methods.

Bu tez çalışmasında, cam tutucu yüzeylere katkısız ve % 1, % 5, % 10 krom (Cr) katkılı HfO2 ince filmler sol-jel daldırma yöntemiyle elde edilmiştir. Elde edilen filmler bir saat 500 C’de tavlamaya bırakılmıştır. Tüm ince filmlerin kalınlıkları foto spektrometre yardımıyla ölçülmüştür. Kalınlıkları tespit edilmiş ince filmlerin yapısal ve optiksel özellikleri X-ışını kırınım deseni (XRD) ve UV-VIS spektrometresi incelenmiştir. Tüm analiz ve sonuçlar literatürde çeşitli yöntemlerle elde edilmiş HfO2 ince film sonuçlarıyla karşılaştırılmış ve katkılama oranının etkisi yorumlanmıştır., In this thesis, HfO2 thin films with additives of 1%, 5%, 10% chromium (Cr) were obtained by sol-gel dipping method on glass-holding surfaces. The films obtained were left to anneal at 500 ° C for one hour. The thicknesses of all thin films were measured with the aid of a photo spectrometer. Structural and optical properties of thin films with thickness determined X-ray diffraction pattern (XRD) and UV-VIS spectrometer were investigated. All analysis and results were compared with HfO2 thin film results obtained by various methods in the literature and the effect of doping ratio was interpreted.