Browsing by Author "Kacus, Hatice"

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Co/Aniline Blue/Silicon Sandwich Hybrid Heterojunction for Photodiode and Low-Temperature Applications
(Sage Publications Ltd, 2021) Kacus, Hatice; Sahin, Yilmaz; Aydogan, Sakir; Incekara, Umit; Yilmaz, Mehmet
The temperature dependence of the current-voltage and room temperature capacitance-voltage measurements of Co/aniline blue/n-Si sandwich-type rectifying device was investigated.Furthermore, the effects of the illumination on the current-voltage measurements were tested with 100 & x202f;mW/cm(2) light intensity, and it was seen that Co/aniline blue/n-Si sandwich-type device showed a clear response to illumination, and it may be a candidate for solar cells or photodiode applications. The rectifying device parameters, such as the barrier height (CYRILLIC CAPITAL LETTER EF), the ideality factor (n), the rectification ratio, and the series resistance (R-s), were obtained as a function of temperature using thermionic emission, Cheung function, and Norde function. The interface state densities versus energy were obtained. The Richardson constant (A*) obtained from the In(I-o/T-2) versus 1000/T plot was much less than the theoretical value for n-Si. The mean Schottky barrier height and the standard deviation (sigma(o)) were calculated using the apparent Schottky barrier height CYRILLIC CAPITAL LETTER EFap versus 1/2 kT plot. So, it has been found to be 1.08 eV and 0.15 V (260-460 K) and 0.79 eV and 0.10 V (100-260 K), respectively. The results were discussed based on the presence of two Gaussian distributions of CYRILLIC CAPITAL LETTER EFb potential in the contact area of Co/aniline blue/n-Si/Al device.
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.
Enhanced Electrical and Optical Characteristics of Co/Phenol Red (PR)/Silicon Hybrid Heterojunction for Photodiode and Thermal Applications
(Springer, 2020) Sahin, Yilmaz; Kacus, Hatice; Aydogan, Sakir; Yilmaz, Mehmet; Incekara, Umit
A Co/phenol red (PR)/n-Si/Al device has been fabricated and its current-voltage (I-V) characteristics measured between 80 K and 460 K. Junction parameters of the device, such as the ideality factor, barrier height, interface state density, and series resistance (R-s), were determined using standard thermionic emission theory, the Cheung function, and the Norde method. The application of these approaches revealed that n varied between 4.66 and 1.70 in the temperature range of 80 K to 460 K, while phi(b) varied between 0.24 eV and 0.83 eV in the same temperature range. These variations of n and phi(b) can be attributed to the barrier height inhomogeneity in the device. Although PR is generally used in biological applications such as cell culture, it has been observed that such Co/phenol red/n-Si/Al devices may be critical candidates for use in thermal sensors and photodiode applications due to their photoresponse and low-temperature operation for reverse-bias I-V measurements. Furthermore, PR is an alternative to semiconductor materials commonly used in such applications.
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.
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.
On Thermal and Optical Sensor Applications of Chitosan Molecule in the Co/Chitosan Hybrid Heterojunction Design
(Springer, 2021) Kacus, Hatice; Aydogan, Sakir; Incekara, Umit; Yilmaz, Mehmet; Biber, Mehmet
Co/Chitosan/p-Si/Al and Co/p-Si devices were made and barrier height and ideality factor values of both devices were determined at room temperature (dark conditions). After the chitosan interlayer was found to improve the device, the thermal and photosensivity properties of the Co/Chitosan/p-Si/Al device were investigated in detail. The current-voltage measurements of Co/Chitosan/p-Si/Al heterojunction were performed in temperature range of 100-460 K and illumination intensity range of 100-400 mW/cm(2). It was seen that the device parameters such as barrier height, ideality factor, series resistance and interface states density were strongly dependent on temperature. Furthermore, the capacitance-voltage (C-V) characteristics of the device were investigated at various frequencies at room temperature. The responsivity (R), detectivity (D*) and rectification ratio (RR) values of the Co/Chitosan/p-Si/Al heterojunction were found to be as a function of illumination intensity. The experimental results show that the fabricated device with chitosan thin film interlayer can be used in various optoelectronic applications, especially applications in low temperature switching devices, energy generation, photodiode and photodetector.
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.
Phenol Red Based Hybrid Photodiode for Optical Detector Applications
(Pergamon-Elsevier Science Ltd, 2020) Kacus, Hatice; Sahin, Yilmaz; Aydogan, Sakir; Incekara, Umit; Yilmaz, Mehmet; Biber, Mehmet
In this study, the phenol red (PR) dye film has been deposited on n-type silicon wafer and SEM, XRD measurements of the film have taken. Then, the PR/n-Si photodiode has been fabricated and (dark) electrical and photoresponse characterization has been analysed. The current-Voltage (I-V) measurements have been carried out at varied light power ranging from 100 mW/cm 2 to 400 mW/cm(2). Rectification ratios (RR) have been determined as a function of illumination intensities and they are determined as 115.47 for 100 mW/cm(2) and 30.26 for 400 100 mW/cm(2), respectively. The ideality factor and the barrier height of the Co/PR/n-Si photodiode have been determined as 2.80 and 0.52 eV, respectively in dark. Therefore, it has been seen that the PR/n-Si photodiode performances are strongly dependent on the incident optical power. Namely, the current density has increased remarkably with the power of light at the same reverse bias voltage and this behavior is explained by strong capability of converting a light signal into an electrical for the PR/n-Si photodiode device. Responsivity (R) and detectivity (D*) of the PR/n-Si photodiode are also plotted as a function of illumination intensities for reverse biases and it is found that both parameters are dependent on the illumination intensity. Finally, the capacitance-voltage (C-V) characteristics of the device have been carried out at various frequencies. Obtained experimental results indicate that the PR dye can be used in various optoelectronic applications.
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.
Schottky Barrier Engineering in Metal/Semiconductor Structures for High Thermal Stability
(IOP Publishing Ltd, 2021) Erdogan, Erman; Yilmaz, Mehmet; Aydogan, Sakir; Incekara, Umit; Kacus, Hatice
In this study, Co/eosin-y/p-Si/Al and Co/eosin-y/n-Si/Al heterojunctions with Schottky barrier were produced and electrical characteristics were investigated in the temperature range 100-460 K at intervals of 20 K. For each device, the barrier heights (phi (b)), ideality factors (n) and series resistance (Rs) values were calculated using different methods from the current-voltage curves. It was observed that the ideality factor and series resistance increased with decreasing temperature, while the height of the barrier decreased. One of the reasons for this change in parameters is the inhomogeneity of the Schottky barrier. The Rs values were found with the help of Cheung functions and Norde functions. The contact parameters obtained from the Cheung functions and those obtained from the Norde function were compared. It was observed that the barrier heights obtained from these methods increased linearly with increasing temperature values. The variation of temperature-dependent interfacial state density versus interfacial state energy was shown. The density of the interfacial state decreased, with increasing interfacial state energy at each temperature value. These characteristics indicate that Co/eosin-y/p-Si/Al and Co/eosin-y/n-Si/Al devices are good candidates for rectifying and thermal sensing applications.