Browsing by Author "Kocyigit, Adem"

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The Comparison of Co/Hematoxylin and Co/Hematoxylin Devices as Rectifier for a Wide Range Temperature
(Elsevier Sci Ltd, 2020) Yilmaz, Mehmet; Kocyigit, Adem; Cirak, Burcu Bozkurt; Kacus, Hatice; Incekara, Umit; Aydogan, Sakir
We employed hematoxylin as interfacial layer between the n- and p-type silicon substrate and cobalt (Co) metallic contact to obtain and compare Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices for a wide range temperature via current-voltage (I-V) characteristics. Furthermore, we studied structural and morphological properties of the hematoxylin thin film by x-ray diffractometer (XRD) and scanning electron microscope (SEM). The temperature range was changed from 100 K to 460 K via 20 K interval for I-V measurements. The Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices exhibited excellent rectifying behaviors for low temperatures, but rectifying ratio (RR) values decreased with increasing temperature at +/- 1 V bias. In addition, the devices showed thermal sensor or detector behavior because current values increased with increasing temperature at reverse biases. The Co/hematoxylin/p-Si device has better stability than Co/hematoxylin/n-Si device at reverse biases for the same temperature values according to stop leakage current with increasing voltage. In addition, the diode parameters such as barrier height, ideality factor and series resistance as well as interface states density were extracted from the I-V measurements and compared in details for various techniques such as thermionic emission theory, Norde and Cheung methods. The diode parameters of the both devices were affected from the temperature changes. The Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices are good candidate for rectifying and thermal sensing applications.
Comparison of N and P Type Si-Based Schottky Photodiode with Interlayered Congo Red Dye
(Elsevier Sci Ltd, 2021) Kocyigit, Adem; Yilmaz, Mehmet; Aydogan, Sakir; Incekara, Umit; Kacus, Hatice
We synthesized a thin film of Au nanoparticles-decorated Congo red (CR) dye on both n-Si and p-Si substrates by the spin coating technique. UV-Vis spectrometer was used to determine the absorbance and band gap of the CR film. Transmission electron microscope (TEM) was used to assess the distribution of Au nanoparticles on the CR dye film. Then, the metal-semiconductor devices were fabricated by evaporation of Co metal and Al ohmic contacts on the front and back surfaces of the CR film-covered substrates, respectively. Thus, Co/CR:Au/n-Si and Co/CR:Au/p-Si Schottky photodiodes were fabricated and characterized by I-V measurements under dark and various light power illumination intensities at room temperature. The devices exhibited good rectifying behaviors and low barrier heights. Various diode parameters such as ideality factor, barrier height, and series resistance values were calculated and compared for the two fabricated photodiodes. The Co/CR:Au/n-Si and Co/ CR:Au/p-Si devices exhibited good photodiode and photodetector properties. Various detection parameters revealed that the obtained devices can be improved for optoelectronic applications.
Effect of Different Sound Atmospheres on SnO2:Sb Thin Films Prepared by Dip Coating Technique
(World Scientific Publ Co Pte Ltd, 2017) Kocyigit, Adem; Ozturk, Erhan; Ejderha, Kadir; Turgut, Guven
Different sound atmosphere effects were investigated on SnO2:Sb thin films, which were deposited with dip coating technique. Two sound atmospheres were used in this study; one of them was nay sound atmosphere for soft sound, another was metallic sound for hard sound. X-ray diffraction (XRD) graphs have indicated that the films have different orientations and structural parameters in quiet room, metallic and soft sound atmospheres. It could be seen from UV Vis spectrometer measurements that films have different band gaps and optical transmittances with changing sound atmospheres. Scanning electron microscope (SEM) and AFM images of the films have been pointed out that surfaces of films have been affected with changing sound atmospheres. The electrical measurements have shown that films have different I-V plots and different sheet resistances with changing sound atmospheres. These sound effects may be used to manage atoms in nano dimensions.
Influence of Illumination Intensity on Electrical Characteristics of Eosin Y Dye-Based Hybrid Photodiode: Comparative Study
(Springer Heidelberg, 2020) Yilmaz, Mehmet; Kocyigit, Adem; Aydogan, Sakir; Incekara, Umit; Sahin, Yilmaz; Kacus, Hatice
We reported the optoelectronic performance of organic/inorganic hybrid junction photodiode based on Eosin y/silicon (Si). For this purpose, we fabricated Eosin y/n-Si and Eosin y/p-Si structures and demonstrated that both devices exhibited strong photodiode characteristics to the increasing light power depending on current-voltage (I-V) measurements. Furthermore, the XRD and SEM analyses of Eosin y film were performed to analyze structural and topographical features of the film. The electrical measurements of Eosin y/n-Si and Eosin y/p-Si photodiodes were carried out in both dark and under various illumination intensities in the range of 100-400 mW/cm(2). The main device parameters, such as ideality factor, barrier height, and responsivities of both devices, were determined from the I-V characteristics. The obtained photocurrent values in reverse biases are higher than the dark current at the same reverse bias for both Eosin y/n-Si and Eosin y/p-Si photodiodes. So, this confirmed that light produces photocurrent due to the formation of electron-hole pairs as a result of light absorption in the Eosin y film. Moreover, the C-V measurements were performed on both photodiodes to characterize capacitive performance of the Eosin y films. The fabricated photodiodes based on Eosin y thin films present great promise for future optoelectronic device applications.
Influences of Pr and Ta Doping Concentration on the Characteristic Features of FTO Thin Film Deposited by Spray Pyrolysis
(Iop Publishing Ltd, 2015) Turgut, Guven; Kocyigit, Adem; Sonmez, Erdal
The Pr and Ta separately doped FTO (10 at.% F incorporated SnO2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.
The Light Detection Performance of the Congo Red Dye in a Schottky Type Photodiode
(Elsevier, 2022) Kocyigit, Adem; Yilmaz, Mehmet; Incekara, Umit; Sahin, Yilmaz; Aydogan, Sakir
The Congo red (CR) (3,3'-[(1,1',-biphenyl)-4,4'-diyl)bis(4-amino-1 amino naphthalene sulphonic)]) is usually used for staining of amyloidosis diseases in the diagnostic application. It shows dichroic behavior, and thus can be employed in optoelectronic applications. In this study, commercially purchased congo red dye was used as an interfacial organic layer for Schottky type photodiode to understand its sensitivity to light. The surface morphology of the CR interlayer was investigated by scanning electron microscopy (SEM), and almost uniform surface was obtained. While cobalt (Co) element was employed as metallic contact, the n -type Si and aluminum (Al) were used as a semiconductor and ohmic contact, respectively. Thus, Co/CR/n-Si device was fabricated by a spin coating and thermal evaporation technique, and characterized by I-V measurements under dark and various light power intensities. The results revealed that the congo red dye can be improved and employed for optoelectronic applications.
Light-Sensing Behaviors of Organic/N-Si Bio-Hybrid Photodiodes Based on Malachite Green (Mg) Organic Dye
(Springer, 2020) Yilmaz, Mehmet; Kocyigit, Adem; Aydogan, Sakir; Incekara, Umit; Tursucu, Ahmet; Kacus, Hatice
We fabricated malachite green (MG) dye-based photodiode between Co metal and n-Si by spin coating technique. The electrical and photoresponse properties of the MG/n-Si photodiode were studied via current-voltage characteristics as a function of the light power intensity in the range of 100 and 400 mW/cm(2). Furthermore, capacitance-voltage measurements were performed on the MG/n-Si photodiode for various frequencies. The photodiode exhibited a good rectification behavior in dark as well as various light illumination intensities with a good photodiode characteristics since generated photocurrent of the MG/n-Si photodiode increased depending on the exposed light intensity. The leakage current was obtained as 2.96 x 10(-5) A under dark and increased to 3.83 x 10(-5) and 11.5 x 10(-5) A for 100 and 400 mW/cm(2) light intensities, respectively. This clear increase at the leakage current with light illumination can be attributed to the generation of electron-hole pairs in MG organic dye as well as semiconductor and forming an internal electrical field in the interface of the photodiode. Furthermore, main photodiode parameters such as ideality factor and barrier height were calculated by thermionic emission theory and Norde method. Both these parameters and responsivity of the photodiode to the light illumination were obtained as function of the light illumination intensity. The capacitance-voltage measurements revealed that the photodiode exhibited capacitance behavior 100 and 1000 kHz frequency range. The photodiode showed same built-in potential and barrier height values with changing frequency, but their values were higher than obtained from thermionic emission theory. The light intensity effects on the MG dye-based photodiode highlights that this dye may be a good candidate for optoelectronic applications.
Molecular Engineering for Donor Electron to Enhance Photodiode Properties of Co/N-Si and Co/P-Si Structures: The Effect of Hematoxylin Interface
(Elsevier GmbH, 2021) Kocyigit, Adem; Yilmaz, Mehmet; Incekara, U. Umit; Aydogan, Sakir; Kacus, Hatice
We used hemotoxylin as interlayer in between Co metal and both n-type and p-type silicon to fabricate Co/hematoxylin/n-Si and Co/hematoxylin/p-Si photodiodes. The photodiodes were characterized and compared by I-V measurements under dark and various light power intensities. The diode parameters were extracted from I-V measurements and discussed in details by thermionic emission theory, Norde and Cheung methods for dark conditions. The photodiode parameters such as photocurrent, light responsivity and detectivity were also studied and compared for two photodiodes. The obtained photodiodes exhibited good rectifying properties, but rectifying ratio (RR) values decreased with increasing light power intensity. The photodiodes exhibited linear photocurrent (Iph), good responsivity and detectivity according to results. However, the responsivity and detectivity values of the Co/hematoxylin/n-Si photodiode slightly decreased with increasing light power intensity while the Co/hematoxylin/p-Si photodiode have almost did not change. The obtained result highlighted that Co/hematoxylin/n-Si and Co/hematoxylin/p-Si photodiodes can be improved for photodiode applications.
Optoelectronic Properties of Co/Pentacene MIS Heterojunction Photodiode
(Elsevier, 2020) Kacus, Hatice; Yilmaz, Mehmet; Kocyigit, Adem; Incekara, Umit; Aydogan, Sakir
The Co/pentacene/n-Si/Al device with the Co/n-Si/Al device was fabricated and characterized by current voltage measurements to understand the effect of the pentacene on electrical properties. The Co/pentacene/nSi/Al device exhibited better rectification properties than reference device. The characteristic parameters such as barrier height, ideality factor, interface states density and series resistance values of the devices were calculated and discussed in details. Furthermore, I-V measurements of the Co/pentacene/n-Si/Al device were performed both in dark and under illumination conditions. The results revealed that the reverse current increased with increasing illumination intensity, and the device exhibited photodiode behaviors as well as good photocunducting characteristics. The C-V characteristics of the Co/pentacene/n-Si/Al were studied for various frequencies to determine the donor carrier concentration and fermi energy level. Experimental results highlights that the Co/pentacene/n-Si/Al device is a good candidate for optoelectronic device applications such as solar cells, photodiode, photodetector due to exhibiting good photoconducting characteristics.
The Performance of Chitosan Layer in Au/N-Si Sandwich Structures as a Barrier Modifier
(Elsevier Sci Ltd, 2020) Kocyigit, Adem; Yilmaz, Mehmet; Aydogan, Sakir; Incekara, Umit; Sahin, Yilmaz
This study focused on the structural, optical and electrical features of chitosan organic layer obtained by spin coating technique both on glass and n-Si substrates. XRD results indicated that chitosan has polycrystalline orthorhombic nature. While optical transmittance spectrum of the chitosan organic layer exhibited an increasing tendency in the visible range, band gap energy value was calculated as 4.23 eV for chitosan by UV-Vis spectrometer. Electrical performance of organic chitosan layer in a Schottky device was studied by fabricating of Au/n-Si and Au/chitosan/n-Si devices. The suitability of Au/chitosan/n-Si sandwich devices in optoelectronic applications were tested under dark and illumination conditions. The Au/chitosan/n-Si sandwich device exhibits good photodiode characteristics. Furthermore, the effect of X-ray radiation doses on the electrical properties of the Au/chitosan/n-Si sandwich device was also investigated. In order to get information about electrical characteristics as a function of X-ray radiation doses, Au/chitosan/n-Si sandwich device was exposed to X-ray radiation in same exposure time and various doses. The results highlighted that the performance of the device with chitosan organic interface layer deteriorated with increasing radiation dose. In addition, the transportation mechanism of chitosan based Schottky device was discussed in details.
The Photosensitive Activity of Organic/Inorganic Hybrid Devices Based on Aniline Blue Dye: Au Nanoparticles (Ab@Au NPs)
(Elsevier Science SA, 2021) Kacus, Hatice; Yilmaz, Mehmet; Incekara, Umit; Kocyigit, Adem; Aydogan, Sakir
In this study, Aniline Blue (AB) synthetic triarylmethane dye and AB:Au NPs mixture films were deposited on n-Si by spin coating technique to form an organic/inorganic hybrid electro-optic device. Thus, Co/AB/n-Si (named D1) and Co/AB:Au NPs (1%)/n-Si (named D2) photoactive devices were fabricated, and current-voltage (I-V) measurements were performed on both devices to investigate electrical properties under dark and various light illumination intensities changes from 100 to 400 mW/cm(2). Sensitivity and responsivity as well as specific detectivity of both devices were obtained depending on the reverse bias voltage for various light intensities. The main device parameters such as ideality factor (n), barrier height (Phi(b)), series resistance (R-s) and experimental interface states density (N-ss) were calculated and discussed in details. The light intensity-dependent I-V measurements revealed that the reverse bias current increased with the increasing of the light intensity and confirmed photodiode behaviors. The illumination coefficient (m) values were also extracted from the light-intensity dependent I-Vcharacteristics and obtained as 0.87 and 1.28 for D1 and D2, respectively. Furthermore, the D2 device exhibited a higher response to the light than D1 due to the surface plasmon resonance effect of Au NPs. The capacitance-voltage (C-V) and conductance-voltage (G -V) characteristics of both devices were also studied in details under dark at 500 kHz applied frequency. As a result, the experimental results highlight that the D1 and D2 devices can be used in various optical applications such as photodiodes, photodetector and carrier storage devices. (C) 2021 Elsevier B.V. All rights reserved.