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Determination Of The Trapping Parameters Of Zns Thin Films Developed By Chemical Spraying Technique, A. Necmetti̇n Yazici, Mustafa Öztaş, Meti̇n Bedi̇r, Refi̇k Kayali
Determination Of The Trapping Parameters Of Zns Thin Films Developed By Chemical Spraying Technique, A. Necmetti̇n Yazici, Mustafa Öztaş, Meti̇n Bedi̇r, Refi̇k Kayali
Turkish Journal of Physics
In this study, the thermoluminescence (TL) glow curves of ZnS thin films developed using chemical spraying technique were carefully investigated and its kinetic parameters were determined with a specially developed computer program. The results of investigations have shown that the trapping states of ZnS thin films could not be analysed by a well-known Randall-Wilkins (RW) or General-Order (GO) models. A detailed investigation of experimental results has indicated that the trapping states have a form that is best described by a distribution of energies. After the comparison of the experimental glow curves of ZnS thin films with theoretically generated glow curves, …
Interface Roughness-Induced Intrassubband Scattering In A Quantum Well Under An Electric Field, Guseyn Behbudoglu Ibragimov
Interface Roughness-Induced Intrassubband Scattering In A Quantum Well Under An Electric Field, Guseyn Behbudoglu Ibragimov
Turkish Journal of Physics
The scattering rates in the lowest subband in a quantum well are calculated for interface roughness scattering when an electric field is applied perpendicular to the layer plane. It is found that the interface roughness scattering rate increases with increase in the electric field. The electric field changes the interface roughness scattering rates drastically in thick QWs compared with those for the zero-field case. This behaviour in the scattering rate gives a new degree of freedom in regions of interest in device applications.
Monte Carlo Simulation Of Electron Transport In Insb, Ö. Özbaş, M. Akarsu
Monte Carlo Simulation Of Electron Transport In Insb, Ö. Özbaş, M. Akarsu
Turkish Journal of Physics
Transport properties of indium antimonide in an electric field have been calculated at 77 K. The calculation shows that ionized impurity scattering plays a dominant role in InSb at low electric field. The mobility, mean energy, and drift velocity are calculated as a function of the electric field strength, and comparison is made with previous theoretical results. Types of the scattering mechanisms and percentage of each mechanism in the total scattering events are determined.
Collapse Of Interstellar Molecular Clouds, E. Rennan Pekünlü, Esra Tiğrak, Di̇cle Zengi̇n
Collapse Of Interstellar Molecular Clouds, E. Rennan Pekünlü, Esra Tiğrak, Di̇cle Zengi̇n
Turkish Journal of Physics
In this paper we systematically investigate the length and time scales of an interstellar molecular cloud for collapse under the influence of self--gravity, magnetic field and Coriolis forces. We used Magnetohydrodynamic (MHD) equations in linearized form in order to explore the dynamical evolution of perturbations. We found that both the Lorentz force and the Coriolis force support the cloud against self contraction, i.e., they introduce stabilizing effect against gravitational instability. Of the two cloud types with the same physical size, only those threaded by an interstellar magnetic field without rotation or those rotating without magnetic field will survive against gravitational …
Investigation Of The Critical Current Density Of Ybacuo High-Temperature Superconductor Ceramic, Ioseb R. Metskhvarishvili, Nodar P. Kekelidze, Magda R. Metskhvarishvili
Investigation Of The Critical Current Density Of Ybacuo High-Temperature Superconductor Ceramic, Ioseb R. Metskhvarishvili, Nodar P. Kekelidze, Magda R. Metskhvarishvili
Turkish Journal of Physics
The method of high harmonics is used to investigate penetration of low magnetic fields within the Y_{1}Ba_{2}Cu_{3}O_{7} high-temperature superconductor ceramic. Given experimental results are explained by the modal dependencies between the value of critical current density and the magnetic induction B: j_{c}(B) = j_{c}(0){\frac{{B_{0}^{2}}} {{B_{0}^{2} + B^{2}}}}.
The Ibm-2 Study For Some Even - Even Platinum Isotopes, Mehmet Baylan, Mehmet Altay Atlihan
The Ibm-2 Study For Some Even - Even Platinum Isotopes, Mehmet Baylan, Mehmet Altay Atlihan
Turkish Journal of Physics
The structure of some even -- even Pt isotopes have been studied within the framework of the interacting boson model. The B(E2), B(M1) and Q(I) values of the above nuclei have been calculated. The numerical results obtained for Pt have been compared with the previous experimental and theoretical values obtained on the basis of the interacting boson model (IBA-2).
Justification Of Spherical Approximations Using Degree Of Linear Polarization Of Hot Electron Luminescence From Gaas Crystal, Mohammad Naeem Khalid, Shazia Yasin
Justification Of Spherical Approximations Using Degree Of Linear Polarization Of Hot Electron Luminescence From Gaas Crystal, Mohammad Naeem Khalid, Shazia Yasin
Turkish Journal of Physics
The anisotropic momentum distribution of photoexcited hot electrons on recombination with holes at the acceptor level produces linearly polarized luminescence. It is found that the degree of linear polarization (DoLP) of the luminescence over the whole width of the first heavy hole peak (0HH) is not constant. Calculations within the spherical approximation show that in bulk GaAs the DoLP over the 0HH peak should vary from zero, at the low energy side, to its maximum value (0.33), at the high energy side of the 0HH peak, for the electric vector of excitation \hat {\boldsymbol e}\vert \vert [110] excitation geometry and …
The Single Step Vmhnc Calculations For Liquid Alkali Metals In The Inverse Problem, Serap Şentürk Dalgiç, Seyfetti̇n Dalgiç, Mehmet Tomak
The Single Step Vmhnc Calculations For Liquid Alkali Metals In The Inverse Problem, Serap Şentürk Dalgiç, Seyfetti̇n Dalgiç, Mehmet Tomak
Turkish Journal of Physics
An effective pair potential \phi (r) for liquid alkali metals close totheir melting points is extracted from an experimental structure factor using the inverse method based on the variational modified hypernetted-chain integral equation theory of liquids (VMHNC). The first order pair potential according to the procedure suggested by de Angelis and March is also presented for comparison. It has been found that the inverted pair potentials of liquid alkali metals scale well.
The Spectral Properties Of Two Interacting Electrons In A Quantum Dot, Mohammad Elsaid
The Spectral Properties Of Two Interacting Electrons In A Quantum Dot, Mohammad Elsaid
Turkish Journal of Physics
The shifted 1/N expansion method is used to study the spectral properties of two interacting electrons confined in a QD, under influence of a uniform magnetic field of arbitrary strength. We give explanation to the transitions in the spin and angular momenta of the QD ground state as the magnetic field sweeps. The electron addition energy is also calculated. Based on different comparisons , the shifted 1/N expansion method gives very good result against various methods used to study the spectra of a two electron QD.
Dispersion Analysis Of Sns And Snse, Haluk Şafak, Mustafa Merdan, Ö. Faruk Yüksel
Dispersion Analysis Of Sns And Snse, Haluk Şafak, Mustafa Merdan, Ö. Faruk Yüksel
Turkish Journal of Physics
The reflectance spectra of single crystals of SnS and SnSe were measured at normal incidence by unpolarized light. The refractive indices of speciemens were calculated by Kramers-Kronig Analysis. On the basis of the Wemple diDomenico single oscillator model, the dispersion parameters were determined. It is found that the parameters obtained by unpolarized light are, in general close to those reported for polarized cases. Morever, a close similarity were observed with E//b polarization for SnS.
Single And Double-Layer Antireflection Coatings On Silicon, İpek Gi̇rgi̇n Kavakli, Kayhan Kantarli
Single And Double-Layer Antireflection Coatings On Silicon, İpek Gi̇rgi̇n Kavakli, Kayhan Kantarli
Turkish Journal of Physics
In this study, the effect of single and double-layer thin film coatings on the reflectance spectrum of silicon surfaces has been investigated. Thin film coatings have been prepared by vacuum evaporation of the materials with suitable refractive index. Reflectance measurements in the visible and near infrared have shown that the coated samples acquire antireflection properties. Thickness and wavelength dependence of the antireflection properties of SiO, CeO_2 and ZnS single-layer coatings with optical thickness of one quarter wavelength has been studied. In double-layer coatings, a thin film of SiO, CeO_2 and ZnS with optical thickness of quarter wavelength were used as …
Modulation Frequency-Dependence Of Photocurrent In Amorphous Si:H P-I-N And Chalcogenides, Bengü Kaplan, Ruhi̇ Kaplan
Modulation Frequency-Dependence Of Photocurrent In Amorphous Si:H P-I-N And Chalcogenides, Bengü Kaplan, Ruhi̇ Kaplan
Turkish Journal of Physics
The effects of modulation frequencies (up to 35 kHz) on the intensity- and temperature-dependence of photocurrent of amorphous (a-) Si:H p-i-n and chalcogenide glasses (a-Se and a-As_2Se_3) were investigated in detail. The variation of exponent \nu, and in the power-law relationship \sigma_{ph} or I_{ph} \propto G^{\nu} between the photoconductivity (or photocurrent) and the generation flux, with modulation frequency in chalcogenide glasses is found to be much stronger than that of a-Si:H p-i-n. The activation energies, calculated from the temperature-dependent photocurrent, were determined at different modulation frequencies. We conclude that the activation energy increases with incresing modulation frequencies at low excitation …
Effects Of The Back Reflector On The Optical Enhancement Factor And Quantum Efficiency Of A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Effects Of The Back Reflector On The Optical Enhancement Factor And Quantum Efficiency Of A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Turkish Journal of Physics
The effect of tin oxide (SnO_2) texture and back reflector (BR) on optical enhancement factor has been extensively investigated in a series of 4 a-Si:H p-i-n solar cells. The internal quantum efficiency QE in the wavelength range 550--750 nm has been analyzed using an optical model. The optical enhancement factor m, which is a wavelength-dependent fitting parameter, represents the increase in optical pathlength relative to the i-layer thickness. Our solar cells, at low or high haze SnO_{2} with an Al BR, have negligible optical enhancement, m < 1.5, representing failure to obtain multiple reflections. This is consistent with large parasitic absorption at the Al/Si interface. Our solar cells at high haze SnO_{2} with ZnO/Al or ZnO/Ag BRs have peak values of m \sim 3-4, with ZnO/Ag having slightly larger values than ZnO/Al. The maximum values of m , and thus the QE increase with reflectivity of the BR, indicates that efficient light trapping needs a very reflective BR to minimize parasitic absorption losses with each pass.
Free-Carrier Absorption In Quantum Well Structures For Alloy-Disorder Scattering, Guseyn Behbudoglu Ibragimov
Free-Carrier Absorption In Quantum Well Structures For Alloy-Disorder Scattering, Guseyn Behbudoglu Ibragimov
Turkish Journal of Physics
A free-carrier absorption theory is given for quantum wells structures in III-V semiconducting materials, for the case when the carriers a scattered by alloy-disorder. It is found that absorption coefficients due to alloy-disorder and to phonons are of the same order. Results are shown that the absorption coefficient decreases with increasing photon frequency and increases with increasing temperature. It is also shown that the absorption coefficient increases with decreasing layer thickness. We also found that absorption in quantum wells structures is enhanced by going to quantum wells of smaller thickness over its value in the bulk III-V semiconducting materials.
Spatial Non-Uniformity Measurements Of Large Area Silicon Photodiodes, Murat Durak, Farhad Samadov, A. Kamuran Türkoğlu
Spatial Non-Uniformity Measurements Of Large Area Silicon Photodiodes, Murat Durak, Farhad Samadov, A. Kamuran Türkoğlu
Turkish Journal of Physics
Accurate determination of the responsivity of silicon photodiodes are highly desired in photometry. The change of responsivity over the surface, the so-called spatial non-uniformity, effects power measurements especially in photodiodes with large active areas. To study this effect, first an intensity-stabilized laser source-optics has been established. A purpose-built step-motor controlled two axis micro mechanical stage has been designed to scan the photodiode surface. In this study, the technique and the results of the uniformity mapping of large area research-grade silicon photodiodes which were measured on the purpose-built set-up are presented.
Formation Energy In Al-Mg Alloy By Positron Annihilation Lifetime Technique (Palt), Mamduh Abedl-Rahman, Emad A. Badawi, Essmat Mahmoud Hassan, Gamal Yahya
Formation Energy In Al-Mg Alloy By Positron Annihilation Lifetime Technique (Palt), Mamduh Abedl-Rahman, Emad A. Badawi, Essmat Mahmoud Hassan, Gamal Yahya
Turkish Journal of Physics
The propose of the present work is to study the interaction of positrons with quenched-in defects and clustered atoms to estimate formation enthalpy in series 50xx of commercial Al-Mg alloys, namely, 5049, 5051,5052 and 5083 at various concentrations: 1.9, 2.09, 2.46 and 4.44 wt % of Mg, respectively. Typically additional impurities were mainly Si, Fe, Cu, Cr and Ti. The monvacancy formation energy of Al-Mg alloys was measured from a trapping model analysis of the T-dependence of the positron lifetime.
Study Of The Effectiveness Of Various Solar Wind Parameters In The Development Of Geomagnetic Storms During Interplanetary Events, -- Badruddin
Turkish Journal of Physics
We have selected some interplanetary events responsible for geomagnetic disturbances of varying magnitude, fairly different from one another. We then tried to find the heliospheric structure (e.g. shock/sheath and/or CME/magnetic cloud) responsible for individual disturbances. We have discussed and inter-compared these structures in their plasma and field parameters as well as in their geomagnetic effects. As a parameter for geomagnetic disturbance we have chosen index Dst, to compare it with variations in field and plasma to heliospheric response structures. We considered parameters such as total field strength, its north-south component, solar wind density, temperature and velocity. In addition, we have …
The Effects Of Nonstoichiometry In High - T_C Superconducting Properties Of Yba_2cu_{3 + X}O_{7 - \Delta}, Beniah Ndudim Onwuagba
The Effects Of Nonstoichiometry In High - T_C Superconducting Properties Of Yba_2cu_{3 + X}O_{7 - \Delta}, Beniah Ndudim Onwuagba
Turkish Journal of Physics
Polycrystalline samples of high T_c superconductor YBa_2Cu_{3 + x}O_{7 - \delta} with 0 \leqslant x \leqslant 0.5 were grown. The effects of nonstoichiometry on the resistance slope above transition temperature T_c and X-ray diffraction patterns for these samples were investigated. In the diffraction patterns obtained, apart from some new features in the peaks, these polycrystalline samples show predominantly 123 phase.
Some Characteristic Properties, Vithal Bhivaba Pujari, V. B. Gaikwad, E. U. Masumdar, P. D. More, L. P. Deshmukh
Some Characteristic Properties, Vithal Bhivaba Pujari, V. B. Gaikwad, E. U. Masumdar, P. D. More, L. P. Deshmukh
Turkish Journal of Physics
This paper presents some information regarding (Cd, Hg) Se materials synthesized by a simple chemical growth process and the structural, optical and electrical transport properties. The growth of these films depends on various preparative parameters and deposition conditions such as concentration of the starting materials, pH, temperature, time, speed of mechanical churning, etc., and the reaction kinetics suggests that the films grow into two different phases: one, initialy an almost linear phase; and second, a saturation phase. The deposits were analysed chemically and by an EDS techniques. It has been seen that more than 70% of the materials taken in …
Mathematical Modeling Of Plasmachemical Processes, Meli̇k-Aslanova Tamilla
Mathematical Modeling Of Plasmachemical Processes, Meli̇k-Aslanova Tamilla
Turkish Journal of Physics
In this research, we studied the kinetics of plasmachemical processes in quasiequilibrium and nonequilibrium conditions. The example of methane conversion into acetylene showed that the most efficient plasmachemical process may be achieved under nonequilibrium conditions, especially, when the reaction was stimulated by vibrational excitation of molecules.
A New Metallicity Calibration For Dwarf Stars With Rgu-Photometry, Sali̇h Karaali̇, Selçuk Bi̇li̇r
A New Metallicity Calibration For Dwarf Stars With Rgu-Photometry, Sali̇h Karaali̇, Selçuk Bi̇li̇r
Turkish Journal of Physics
We have adopted the procedure of Carney to obtain a metallicity calibration for dwarfs utilising RGU-photometry. For this purpose we selected 76 dwarfs of different metallicities from Carney and from Strobel et al., and evaluated their \delta (U-G) ultra-violet excess relative to the Hyades by transforming UBV magnitudes to RGU via the metallicity dependent equations of Ak-Güngör. The \delta_{0.6}/\delta M normalized factors of Sandage transform \delta (U-G) excess at any G-R to \delta \equiv \delta_{1.08}, i.e. the ultra-violet excess at G-R = 1.08 mag, corresponding to B-V = 0.60 mag in the UBV-system. Finally, the (\delta, [Fe/H]) pairs were shown …
Effect Of The Oxygen/Halogen Ratio On The Physical Properties Of Some Sodium-Boro-Vanadate Glasses, Ahmed Gamal El-Din Mostafa
Effect Of The Oxygen/Halogen Ratio On The Physical Properties Of Some Sodium-Boro-Vanadate Glasses, Ahmed Gamal El-Din Mostafa
Turkish Journal of Physics
Four different glass systems of the sodium boro-vanadate type containing halogen ions, were prepared by melting at 1000°C for three hours and annealed at 300°C. These glasses were investigated using dc conductivity, density, molar volume and magnetic susceptibility measurements. It was found that the activation energy shows a decrease as the halogen ions were increased, which was attributed to the increase in the mobility of sodium ions and the gradual formation of some terminal non-bridging halogens, in addition to the electron hopping between the different oxidation states of vanadium. The activation energy values for glasses containing iodine ions was less …
Paramagnetic Defects In \Gamma-Irradiated, Pure And Doped (With As, Cl And Br) Selenium, Ibrahimgizi Salima Mekhtieva, Ibrahimogli Namig Ibragimov, Isaogli Abasat Isaev, Zeinalogli Vasif Zeinalov, Arifogli Eldar Mamedov
Paramagnetic Defects In \Gamma-Irradiated, Pure And Doped (With As, Cl And Br) Selenium, Ibrahimgizi Salima Mekhtieva, Ibrahimogli Namig Ibragimov, Isaogli Abasat Isaev, Zeinalogli Vasif Zeinalov, Arifogli Eldar Mamedov
Turkish Journal of Physics
This paper presents results of an EPR spectrum investigation of \gamma-irradiated (Co^{60} dose 10^{7} Rad) glasses Se, SeCl_{x}, Se_{0.95}As_{0.05}Cl_{x} and Se_{0.95}As_{0.05}Br_{x} (x=0.001--0.1) at 77 K. An analysis of spectra reveals that two types of paramagnetic radiation-induced defects arise (broken bonds localized on Se and As atoms) from the irradiation of such chalcogenide glasses.
Monitoring The Effect Of Recrystallization And Quenching In Almg_{X} Alloy By Pat, A. Ashour, Nour Zaki El-Said, Emad A. Badawi
Monitoring The Effect Of Recrystallization And Quenching In Almg_{X} Alloy By Pat, A. Ashour, Nour Zaki El-Said, Emad A. Badawi
Turkish Journal of Physics
Positron annihilation technique (PAT) lifetime measurements have been carried out on AlMg_{x} samples (x = 0.23, 0.85, 1.27 and 1.4 at %) with point defects and dislocations introduced by plastic deformation at room temperature. Clustering of vacancies was observed by quenching using PAT. The samples were annealed at 573 K for 12 hours to homogenize and divided into two sets. The first set of AlMg_{x} (x = 0.23, 0.85 and 1.4 at %) was deformed to 10, 25 and 35% thickness reduction. Isochronal annealing was studied in the range of 300-550 K. In the second set of measurements, AlMg_{x} (x …
Characterization Of The Sno_{2}/P Contact Resistance And Sno_{2} Properties In Operating A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Characterization Of The Sno_{2}/P Contact Resistance And Sno_{2} Properties In Operating A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Turkish Journal of Physics
A method is presented to characterize the TCO/p contact and the TCO sheet resistance in a-Si TCO/p-i-n superstrate devices. It is extremely useful for understanding resistance losses in modulus and diagnosing how plasma processing influences the TCO layers. Analysis of 4-terminal dark J-V measurements as a function of temperature on devices with varying TCO geometry yields the TCO/p contact resistance R_{TCO/p}, its activation energy E_{a} or barrier height, and the TCO sheet resistance R_{SH} in an integrated device structure. The method is applied to devices fabricated on different brands of commercial SnO_{2} substrates with different p-layers. Important new results are …
Measurement Of Photon-Induced K X-Rays Production Cross Sections For Elements With 62 \Le Z \Le 74, Sabri̇ye Seven
Measurement Of Photon-Induced K X-Rays Production Cross Sections For Elements With 62 \Le Z \Le 74, Sabri̇ye Seven
Turkish Journal of Physics
X-ray production cross sections of K\alpha_{1}, K\alpha_{2}, K\beta'_{1} (= K\beta {\ss}_{1} + K\beta_{3} + K\beta_{5}) and K\beta'_{2} (= K\beta_{2} + K\beta_{4} + transitions from higher levels) lines have been measured and theoretically calculated for six elements with 62 \le Z \le 74 at excitation energy of 78.706 keV, the weighted avarage of K conversion x-rays emitted from Bi. The experimental results were compared with theoretically predicted values based on relativistic Hartree-Slater and Hartree-Fock theories, a comparison that was found to be in good agreement to within the experimental uncertainties.
Production And Structure Of Rapidly Solidified Al-Si Alloys, Orhan Uzun, Tuncay Karaaslan, Mustafa Keski̇n
Production And Structure Of Rapidly Solidified Al-Si Alloys, Orhan Uzun, Tuncay Karaaslan, Mustafa Keski̇n
Turkish Journal of Physics
Al-Si alloys with compositions 8, 12, 16wt% Si were manufactured by chill casting and melt-spinning (MS) methods. The resulting ribbon samples have been characterized by optical and scanning electron microscopy (SEM) and X-ray diffractometry and compared with their ingot counterparts. Microstructural examinations revealed that microstructures of the melt-spun ribbons were quite fine compared to their ingot counterparts. Both XRD analyses and microstructural examinations indicated that the solubility of Si in \alpha -Al phase was nearly complete.