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Öğe Synthesis and analysis of TiO2 nanotubes by electrochemical anodization and machine learning method for hydrogen sensors(Elsevier, 2022) Işık, Eşme; Taşyürek, Lütfi Bilal; Işık, İbrahim; Kılınç, NecmettinThe conductometric hydrogen gas sensors were used to explore TiO2 nanotubes in this study. TiO2 nanotubes are synthesized by anodization of the titanium foils using a neutral 0.5% and 1% (wt) NH4F in glycerol solution depending on anodization time and anodization voltage at the temperature of 20 °C. The amorphous, rutile and anatase phases of TiO2 are observed for as-prepared TiO2 nanotubes, annealed at 700 and 300 °C, respectively. The diameters of the nanotubes grow as the anodization time and voltage increase, according to scanning electron microscopy (SEM) images. The inner diameter of nanotubes is changed between ~70 nm to ~225 nm. Hydrogen sensing properties of Ti/TiO2 nanotubes/Pd device has been tested at room temperature under concertation range from 0.5% to 10% depending on the crystalline phase. The highest sensor response is observed for anatase crystalline TiO2 nanotubes. Typical Schottky-type behavior is observed from the I-V measurement. All the fabricated nanotube diameters are also simulated by using Support Vector Machine and Artificial Neural Network models. And also, some of the nanotube diameters which are not obtained experimentally (anodization voltage of 70 V) are estimated using the Support Vector Machine and Artificial Neural Network models. In addition, an analytical model is also proposed using Jacobi numeric analysis method alternative to the simulation model for the nanotube diameter. Finally, the analytical, simulation, and experimental results are compared, and the best result is obtained using the 1 Hidden Layer Artificial Neural Network model.Öğe Analyzing of Alzheimer’s Disease Based on Biomedical and Socio-Economic Approach Using Molecular Communication, Artificial Neural Network, and Random Forest Models(Multidisciplinary Digital Publishing Institute (MDPI), 2022) Bayraktar, Yüksel; Işık, Esme; Işık, İbrahim; Özyılmaz, Ayfer; Toprak, Metin; Kahraman Güloğlu, Fatma; Aydın, SerdarAlzheimer’s disease will affect more people with increases in the elderly population, as the elderly population of countries everywhere generally rises significantly. However, other factors such as regional climates, environmental conditions and even eating and drinking habits may trigger Alzheimer’s disease or affect the life quality of individuals already suffering from this disease. Today, the subject of biomedical engineering is being studied intensively by many researchers considering that it has the potential to produce solutions to various diseases such as Alzheimer’s caused by problems in molecule or cell communication. In this study, firstly, a molecular communication model with the potential to be used in the treatment and/or diagnosis of Alzheimer’s disease was proposed, and its results were analyzed with an artificial neural network model. Secondly, the ratio of people suffering from Alzheimer’s disease to the total population, along with data of educational status, income inequality, poverty threshold, and the number of the poor in Turkey were subjected to detailed distribution analysis by using the random forest model statistically. As a result of the study, it was determined that a higher income level was causally associated with a lower risk of Alzheimer’s disease.Öğe Thermoluminescence characteristics of calcite with a Gaussian process regression model of machine learning(Wiley, 2022) Işık, EşmeThermoluminescence (TL) is defined as a luminescence phenomenon that can be detected when an insulator or semiconductor is thermally stimulated. Defective crystals store radiation until they are stimulated. Thermoluminescence is a method of monitoring the absorbed dose of dosimeters. The irradiation crystal is heated to 500°C to display the absorbed dose as a luminescent light. The TL dosimetric properties of calcite obtained from nature were investigated in this study. Machine learning was also examined using Gaussian process regression (GPR) for stimulated TL characteristics. According to the experimental output, the TL glow curve had two main peaks located at 90°C and 240°C with good dosimetric properties. In the four regression models of GPR, the data for the heating rate of 3°C s-1 have the lowest residual.Öğe Socio-Economic, Demographic and Health Determinants of the COVID-19 Outbreak(MDPI, 2022) Özyılmaz, Ayfer; Bayraktar, Yüksel; Toprak, Metin; Işık, Esme; Güloğlu, Tuncay; Aydın, Serdar; Olgun, Mehmet Fırat; Younis, MustafaObjective: In this study, the effects of social and health indicators affecting the number of cases and deaths of the COVID-19 pandemic were examined. For the determinants of the number of cases and deaths, four models consisting of social and health indicators were created. Methods: In this quantitative research, 93 countries in the model were used to obtain determinants of the confirmed cases and determinants of the COVID-19 fatalities. Results: The results obtained from Model I, in which the number of cases was examined with social indicators, showed that the number of tourists, the population between the ages of 15 and 64, and institutionalization had a positive effect on the number of cases. The results obtained from the health indicators of the number of cases show that cigarette consumption affects the number of cases positively in the 50th quantile, the death rate under the age of five affects the number of cases negatively in all quantiles, and vaccination positively affects the number of cases in 25th and 75th quantile values. Findings from social indicators of the number of COVID-19 deaths show that life expectancy negatively affects the number of deaths in the 25th and 50th quantiles. The population over the age of 65 and CO2 positively affect the number of deaths at the 25th, 50th, and 75th quantiles. There is a non-linear relationship between the number of cases and the number of deaths at the 50th and 75th quantile values. An increase in the number of cases increases the number of deaths to the turning point; after the turning point, an increase in the number of cases decreases the death rate. Herd immunity has an important role in obtaining this finding. As a health indicator, it was seen that the number of cases positively affected the number of deaths in the 50th and 75th quantile values and the vaccination rate in the 25th and 75th quantile values. Diabetes affects the number of deaths positively in the 75th quantile. Conclusion: The population aged 15–64 has a strong impact on COVID-19 cases, but in COVID-19 deaths, life expectancy is a strong variable. On the other hand, it has been found that vaccination and the number of cases interaction term has an effect on the mortality rate. The number of cases has a non-linear effect on the number of deaths.Öğe Dispersion characteristics of silk fibroin protein polymer(2020) Taşyürek, Lütfü Bilal; Gündüz, BayramSilk is a natural protein fiber and is widely used in textile technology. Apart from textile technology, silk is preferred in many fields and applications such as biomedical because of its superior advantages. In this study, the fibroin silk solution was used as a biomaterial. The refractive indices of silk fibroin (SF) protein polymer were obtained and the refractive index dispersion of the SF protein polymer was analyzed in detail.Öğe Comparison of the Mobile and Fixed Nano/Micro-Scale Systems by Using Monte Carlo Simulation for Different Viscosity Values(Iğdır Üniversitesi, 2021) Işık, Esme; Işık, İbrahimNano networks that are defined as a communication of nano-sized devices (Nano Machines) are a new nano/micro-scale system subject. In this study, on the contrary to the literature, a mobile nano network model has been used to analyze the proposed system in a different viscosity environment by using some Physics law. Because it is known that besides the molecules, which transport information between transmitter and receiver, the transmitter and receiver parts of the biological cells can be mobile in the blood or any other fluid media. In addition, the effect of viscosity which is an important part of the environment of the nano-device systems and distance between transmitter and receiver are analyzed detailed in Matlab with analytical and simulation results by comparing the fixed and mobile nano scale systems. It is concluded that when the receiver and transmitter are mobile, distance between them changes and finally this affects the probability of the received molecules at the receiver. As is expected, the fraction of received molecules is obtained the highest when the viscosity of the environment and distance are the lowest for both fixed and mobile system models. Also positions of receiver and transmitter show that when the distance of transmitter and receiver increases from the origin, fraction of received molecules decreases.Öğe A study on Optical Applications of Silk Fibroin Biomaterial(2020) Gündüz, Bayram; Buldurun, KenanSilk ?broin (SF) is a natural substitute used in biological medicine for its good biocompatibility and biodegradability. Compared to other easily degradable (biodegradable) materials, they exhibit excellent properties, such as excellent mechanical properties, optical properties and electrical insulation, which are advantageous in the development of materials made from silk bromine, flexible electronics. In here, optoelectronic parameters such as optical band gap, transmittance, dielectric constant and conductivity components of the silk fibroin solution were obtained and were discussed for biomaterial applications.Öğe Effect of the Viscocity on Molecule Reception Ratio for Mobile Nano Systems(Bingöl Üniversitesi, 2021) Işık, Esme; Işık, İbrahim; Tağluk, M. EminStudies regarding Molecular Communication via Diffusion (MCvD) are considered to highly contribute to the developments in the field of nano-technology. Therefore, in this study, software-based a new MC model that could potentially be used in nano-scale systems was developed and analyzed in terms of communication performance. The information about the carrier particles used in such communication systems consists of biological components such as DNA and protein components. MC model that can possibly be used in nano-scale systems is analyzed in terms of channel performance of communication such as viscosity of the medium. The physical properties of the channel models such as viscosity and hitting probability of received molecules are analyzed in this study using the mobile point transmitter and spherical receiver. As a result, the probability of a molecule reception of the receiver and number of received molecules increase with increasing viscosity.Öğe Şüt Kanalları Üzerine Yerleştirilen Blokların Enerji Sönümlenme Etkilerinin Araştırılması(Su Vakfı, 2020) Aydoğdu, Mahmut; Dursun, Ömerul FarukAçık kanal akımlarında, akımın sahip olduğu fazla miktardaki enerjiyi sönümlemek için enerji kırıcı yapılar inşa edilir. Bazen de akım, enerji kırıcı yapıya ulaşmadan enerjisini azaltacak engel bloklarına maruz bırakılır. Bu suretle akımın fazla hızlanması engellendiği gibi enerji kırıcı yapının boyutları da azaltılır. Kaskatlarda veya yüksek eğimli bir şüt kanalında enerji kırıcı bloklar kullanılarak hızların azaltılması, barajların ve benzer hidrolik yapıların güvenliği açısından oldukça önemlidir. Bu çalışmada, enerji kırıcı blokların enerji sönümleme oranları araştırılmıştır. Açık kanal içerisine dizilmiş olan küp blokların iki farklı dizilim şekli için enerji sönümleme oranındaki değişimler gözlenmiştir. Yapılan bu deneylerde; 2 nolu blok diziliminin 1 nolu dizilim şekline göre daha fazla enerji kırdığı ortaya çıkmıştır. Debi miktarı arttıkça, kırılan enerji miktarının blok diziliminden daha az etkilendiği belirlenmiştir. Bu çalışmada sonuç olarak, aynı özelliklere sahip blokların kanal içerisinde dizilim şeklini değiştirerek daha fazla enerji kırılabileceği gözlemlenmiştir.Öğe Nano Sistemlerde Hücreler Arası Haberleşmenin Analiz Edilmesi(Harun TAŞKIN, 2021) Işık, İbrahim; Işık, Esme; Tağluk, M.EminFarklı canlı türleri farklı zeka seviyelerine sahip olduğundan, akıl ve zekanın beyinle bir bağlantısının olabileceği düşünülmektedir. Akıl, bilinç ve zaka insanlık tarihinden beri bilim insanlarını etkileyen en etkileyici kavramlar arasında olmuştur. Ancak bilinci, yalnızca sinir sisteminin veya beynin bir ürünü olarak görmenin de uygun olmayacağı düşünülmektedir. Beynin, yaratıcılık, düşünce ve duygu vs. gibi organizasyonlardan sorumlu olduğu bilinmektedir. Bilincin varlığı için ise sinir sistemi veya beynin gerekli olmadığı birçok çalışma tarafından daha önce ispatlanmıştır. Bunun en basit örneği bitkilerin herhangi bir sinir sistemi veya beyni olmamasına rağmen güneşe yönelebilme bilinçlerinin olmasıdır. Bilinçli bir nano haberleşme modelin tasarlanabilmesi için öncelikle biyolojik canlıların ürettiği sinyallerin tasarlanan bu model ile elde edilmesi gerektiği düşünülmektedir. Çünkü canlıların bütün hücrelerinin bu sinyaller (aksiyon potansiyel) aracılığı ile birbiri arasında iletişim kurduklarına inanılmaktadır. Bu sebeple bu çalışma kapsamında, biyolojik hücrelerin ürettiği aksiyon potansiyel sinyaline neredeyse birebir benzer sinyal üreten elektronik bir devre tasarlanmıştır. Üretilen aksiyon potansiyelin gerçek bir nöron hücresinin ürettiği aksiyon potansiyele yakın olabilmesi için literatürdeki elektronik modellerde kullanılan elemanlar incelendikten sonra böyle bir sistem geliştirilmiş ve bu sistemde kullanılan parametrelerin değeri de yine üretilen aksiyon potansiyelin benzerliğini arttıracak şekilde uzun süren denemeler sonunda hassas bir şekilde tespit edilmiştir. Daha sonra ise tasarlanan model ile iki hücrenin birbiri ile haberleşmesinden elde edilen veriler incelenmiştir.Öğe Dose and fading time estimation of glass ceramic by using artificial neural network method(2021) Işık, İbrahim; Işık, Esme; Toktamış, HüseyinCeramic materials commonly used for dental prosthetics and restorations shows luminescent properties. Dental ceramics are considered the most natural-looking restorative materials for aesthetic rehabilitation due to their transparency. They are commonly used for dose response and fading assessment by using thermoluminescence method in various fields of dosimetric applications. In present study, we use artificial neural networks (ANN) toolbox of Matlab to predict irradiation dose and fading time using glow curve data from dental glass ceramic which is thermoluminescent (TL) dosimetric material. Temperature, dose value and fading time are used for input and TL intensity used for output component of the proposed ANN model. 18 neurons are used for hidden layer to analyze the experimental results of the model. Experimental and simulation results are compared and similarity is found as about 99 % in this present study.Öğe Interference and molecule reception probability analysis in nano/micro scale communication systems using Fick’s diffusion law(Gazi Üniversitesi, 2022) Işık, İbrahim; Tağluk, Mehmet EminNano ve mikro ölçekteki sistemlerin iletişim mekanizmasını modellemek için canlıların kullandığı nano-ölçekteki elektro-kimyasal haberleşme sistemlerinden esinlenerek (biyolojik esinli) yeni haberleşme tekniklerinin geliştirilmesi üzerine son zamanlarda yoğun bir şekilde çalışma yapılmaktadır. Bilgi alışverişinde taşıyıcı olarak kimyasal sinyallerin kullanıldığı bu alan nano/mikro ölçekli haberleşme (NMÖH) olarak bilinmektedir. Moleküler haberleşme sistemlerinde iletim için kullanılan bilgi parçacıkları protein, DNA gibi biyolojik bileşenlerden oluşmaktadır. NMÖH konusu ile ilgili yapılacak çalışmaların, günümüzde henüz tedavisi olmayan bazı hastalıkların teşhis ve tedavinde kullanılan yeni nesil nano-teknoloji alandaki gelişmelere büyük katkılar sağlayacağı düşünülmektedir. Bu sebeple, nano-ölçekli sistemlerde kullanılma potansiyeli olabilecek yeni bir NMÖH modeli yazılım tabanlı olarak Matlab ortamında geliştirilerek burada analiz edilmiştir. Yazılım tabanlı olarak tasarlanan NMÖH modelinde, ilk olarak moleküllerin iletildiği difüzyon ortamı ve bu ortamda iletişim performansını etkileyen faktörlerden biri olan difüzyon sabiti, Fick yasası gibi temel fizik kanunları kullanılarak yeniden türetilmiştir. Daha sonra ise alıcı topolojisi küre, küp ve dikdörtgen prizma gibi değişik formlarda denenerek alıcının sinyal iletim oranı arttırılmaya ve iletim sırasında meydana gelen moleküller arası girişim düşürülmeye çalışılmıştır. Küp alıcı modelinin kullanılması ile sinyal iletim oranının arttığı ve girişimin düştüğü görülmüştür. Önerilen NMÖH modelinin, başta Alzaymır olmak üzere hücrelerin yanlış ve/veya eksik iletişiminden kaynaklı birçok hastalığın teşhis ve tedavisinde kullanılabilecek potansiyelde olduğu düşünülmektedir.Öğe Comparison of oxygen transfer efficiency using new types of baffle blocks(ICE Publishing, 2021) Aydoğdu, Mahmut; Dursun, Ömer FarukOxygen is needed for the natural ecological balance and organisms in water. Dissolved Oxygen (DO) in water can be increased naturally in different ways. In particular, some hydraulic structures are designed so re-oxygenation of water occurs spontaneously in a short distance and time. Baffled chutes are designed to dissipate the energy of flow in irrigation systems, wastewater systems, and stormwater systems. Staggered baffle blocks placed in a chute channel not only dissipate the energy of the water but also allow free oxygen transition between the water-air surface with the hydraulic jumps. While the water flows over the blocks, between the blocks, and around the blocks, entrained air bubbles pass into the water. The entrained air bubbles in the flow start to dissolve within the chute. Thus, the oxygen concentration in water increases by itself. In this study, the amount of DO was determined for baffle blocks with 6 different geometric shapes, different flow discharges and angle variations (10°???56°). These tests demonstrated that the oxygen efficiency of the new baffle blocks proposed in this study is very effective. Type-1 block provided more oxygen efficiency for steep chutes, while Type-6 block provided more efficiency for low slope chutes.Öğe Structural and magnetic characterisation of Co substituted Ni2MnSb Heusler alloy: effect of cobalt substitution on magnetism and Curie temperature(Taylor and Francis Ltd., 2021) Öz, Erdinç; Ak, Fermin; Saatci, BuketIn this study, Ni2-xCo x MnSb full-Heusler alloys (1.00 ? x ? 1.75) were prepared by arc melting process, and examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and SQUID. The L21 crystal structure of the synthesised Heusler alloy was confirmed by XRD patterns, and it was observed that the use of Co instead of Ni caused a decrease in the interatomic distance. The magnetisation results revealed that all samples show ferromagnetic (FM) behaviour, and substitution Co for Ni leads to increasing FM interactions in the samples. The calculated magnetic moment per formula unit increase from 4.38 µB(x =1) to 5.17 µB (x =1.75). On the other hand, the increase in FM interaction caused an increase in ferromagnetic-paramagnetic (PM) phase transition (T C) temperatures from 513 (x =1) to 568 K (x =1.75). The ability to control the Curie temperature with Co substitution makes these alloys suitable candidates for future spintronics and magnetoelectronic applications.Öğe β-Carotene Stability and Some Physicochemical Properties of Apricot Juice Powders Obtained by Using Maltodextrins with Different Dextrose Equivalents(Wiley-VCH Verlag, 2020) Arslan, Tamer; Durmaz, GökhanIn this study, apricot juice powders (AJPs) are obtained via freeze-drying using different maltodextrins (MDs) as carrier agents. The Hacıhaliloğlu cultivar, which is the most common variety in Turkey, is used as an apricot sample. Three different MDs: low (4–7), medium (13–17), and high (17–20) dextrose equivalence (DE) are used as the carrier agent. The powders obtained are subjected to accelerated oxidation at 55 °C, and the stability of ?-carotene in the AJPs is determined. Some physicochemical properties, such as the glass transition temperature, microstructure, bulk density, color, moisture, solubility, degree of caking, and hygroscopicity, are also determined. The results show that after a 20 day period of oxidation, the remaining ?-carotene in the control sample is 24% of the initial value, whereas for low, medium, and high DE MD samples, it is measured to be 47%, 60%, and 57% of the initial concentration, respectively. There is no significant difference in the content of surface carotenoids between the control and the samples with added MD. In contrast, according to other quality attributes like hygroscopicity, caking, moisture content, and solubility, the best results are obtained from the low DE MD sample.Öğe Analyzing of the diffusion constant on the nano-scale systems by using artificial neural networks(American Institute of Physics, 2021) Işık, EsmeThe study concerning nano-scale systems is considered to highly contribute to the developments in the field of nano-technology where many models have been proposed in the literature. The information is carried by molecules in the diffusion medium of the models. Channel parameters such as the diffusion constant are very important for communication of the molecules between the transmitter and the receiver. The physical properties of the carriers and the density of the medium are also very important for the transfer of information. In this study, the number of received molecules is analyzed with respect to the environmental parameters of the channel such as viscosity and the diffusion constant. First, the diffusion constant is obtained analytically by using the Stokes–Einstein equation, and then a new model was developed in Matlab and analyzed in terms of performance of the system concerning channel parameters such as the diffusion constant. Second, the diffusion constant of the medium was predicted by using an artificial neural network and compared with the simulation results. The different diffusion constant values have been used in the environment contrary to the literature to obtain the number of received molecules. The predicted values of the number of received molecules for D = 75 µm2/s and D = 150 µm2/s were also obtained for mobile and fixed system models. The difference between predicted and simulation values is obtained as ±0.5 by using residual analysis.Öğe The current transformer mechanism and structural properties of novel Al/BODIPY/pSi and Au/BODIPY/pSi heterojunctions(Elsevier, 2021) Sevgili, Ömer; Taşyürek, Lütfi Bilal; Bayındır, Sinan; Orak, İkram; Çalışkan, ErayIn this study, the performance of BODIPY dye-based organic layers was investigated with diode applications. Gold (Au) and aluminum (Al) rectifier contacts were evaporated on the BODIPY dye-based organic layers. The effect of the Au and Al metal contacts were examined under different illumination and frequency conditions. The surface morphology of the organic layers was characterized with an atomic force microscopy. The electrical measurements, such as current-voltage, capacitance-voltage and conductance-voltage, were measured in the dark and at room temperature. The photovoltaic performance of the organic layers was investigated under various illumination conditions. Eight devices were made with four different organic materials using the Au and Al metal contacts. The effects of Al and Au on the devices were compared with the electrical measurements. It was concluded that the performance of the devices made with Au was better, as there was oxidation in the devices made with Al.Öğe Synthesis of nickel nanoparticles-deposited strontium titanate nanocubes (Ni-STO) and heterojunction electrical applications over a wide temperature range(Elsevier, 2021) Taşyürek, Lütfi Bilal; Aydoğan, Şakir; Sevim, Melike; Çaldıran, ZakirIn the present study, the structural properties of nickel nanoparticles-deposited strontium titanate nanocubes (Ni-STO) were examined by taking XRD, ICP-MS, TEM and SEM images. Temperature-dependent capacitance–voltage (C-V) and current–voltage (I-V) measurements were made for the electrical characterization of the Ni/Ni-STO/n-Si heterojunction devices produced. As the temperature increases from 80 K to 400 K, the ideality factor (n) decreases from 2.30 to 1.02 while barrier height (BH) increases from 0.27 eV to 0.80 eV. In the heterojunction device between Ni-STO and n-type Si, electrons can be captured at the Schottky barrier interface and recombinations can be reduced. Devices produced with Ni-STO material had a positive effect on performance compared to the devices produced with STO in previous studies. The electrical parameters obtained give compatible results as a function of temperature. Metal deposited STOs are potential candidates for temperature-dependent sensors and electrical devices.Öğe The Importance of Polymorphism Dependent Aggregation Induced Enhanced Emission of the Acrylonitrile Derivative: Helical J Type and Antiparallel H Type Stacking Modes(Wiley-Blackwell, 2021) Yakalı, Gül; Çoba, Mustafa B.; Özen, Furkan; Özen, Leyla B.; Gündüz, Bayram; Turgut Cin, GünseliIn this study to analyze the structure-property relationship of synthesized ?-conjugated acrylonitrile derivative in terms of polymorphism dependent emission and conformational polymorphism, single crystal x-ray diffraction method, photophysical and theoretical studies were performed. The fluorescent molecule with two polymorphic structure were presented to demonstrate the effect of the molecular conformation and stacking type on the polymorphism dependent emission in aggregate state. According to results of crystallography and photophysical studies, both form of the molecule displayed aggregation induced enhanced emission (AIEE) property in the solid phase due to the restricted intramolecular rotation (RIR) and favourable stacking interactions including the antiparallel H type, J type stacking modes and intramolecular charge transfer (ICT) process. As a result, J type and antiparallel H type stacking mode with the restricted intramolecular rotation make the crystals higly emissive in solid phase. We believe that, studied two polymorphs will be best candidates for the ?-conjugated acrylonitrile derivatives in the optoelectronic field. Moreover, this study will provide an overview of the importance of conformational polymorphism, stacking type on fluorescence properties of the polymorphic structures and propose new ways for targeted polymorphic molecular design strategies in acrylonitrile derivatives.Öğe The effect of different frequencies and illuminations on the electrical behavior of MoO3/Si heterojunctions(Springer, 2021) Çaldıran, Zakir; Taşyürek, Lütfi Bilal; Nuhoğlu, YasinIn this study, the rectifier properties of the transition metal oxide group n-type semiconductor molybdenum trioxide (MoO3) were investigated. The MoO3 material is a suitable material for the heterojunction structures with AFM, SEM, XRD, and 3D optical profilometer such as structural and morphological characterization result showed. Current–voltage (I-V), capacitance–voltage (C-V), and conductance-voltage (G-V) measurements of Cr/MoO3/n-Si and Cr/MoO3/p-Si heterojunction devices were made in dark and different illuminations at 300 K. The basic diode parameters were determined by using Thermionic emission (TE), and Cheung and Norde method from the I-V characteristics of the devices in dark conditions. The ideality factors of Cr/MoO3/n-Si and Cr/MoO3/p-Si devices were calculated as 1.25 and 1.22, respectively, and barrier heights of 0.69 and 0.71 eV of the devices were calculated by TE method. These results showed that the MoO3/Si heterojunction has rectifier properties. The high values of ideality can be attributed to the inhomogeneities at the interface and the series resistance. In addition, the photoconductivity properties were examined of the devices at 50 and 100 mW/cm2 illuminations. From the experimental results obtained, it was concluded that the devices can be used as photodiodes as well as showing good rectifier properties.
