Yazar "Kasapoglu, Esin" seçeneğine göre listele
Listeleniyor 1 - 15 / 15
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe The diamagnetic susceptibilities of donors in quantum wells with anisotropic effective mass(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2009) Kasapoglu, Esin; Ungan, Fatih; Sari, Hueseyin; Soekmen, IsmailThe diamagnetic susceptibility of a hydrogenic donor placed in Si, Ge and GaAs quantum wells with infinite confinement potential which have different effective mass anisotropy parameters (gamma = m(perpendicular to)L/m(parallel to)) has been investigated as a function of the well sizes. The binding energies of the donor have also been computed using a trial wave function with two parameters in the framework of the effective mass approximation. It has been observed that the diamagnetic susceptibility of the donor in the anisotropic materials converges rapidly to the bulk limit as the well size increases. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Effect of Intense Laser Field in Gaussian Quantum Well With Position-Dependent Effective Mass(Wiley-V C H Verlag Gmbh, 2019) Sari, Huseyin; Kasapoglu, Esin; Sakiroglu, Serpil; Sokmen, Ismail; Duque, Carlos A.In this paper, the effects of the intense laser field (ILF) and position dependent mass (PDM) on the electronic structure in a Gaussian quantum well are theoretically deduced by using the diagonalization method for obtaining energy levels and corresponding wave functions. We find that, in the case of narrow PDM distribution, the dependence of the energy levels on the effective length of the electron mass distribution becomes more apparent, and the evolution of the dressed mass with ILF is significant. Given this feature, it is more meaningful to take into consideration the PDM of the electron in the low dimensional semiconductor heterostructures under the ILF.Öğe The effect of magnetic field on the impurity binding energy of shallow donor impurities in a Ga1-xInxNyAs1-y/GaAs quantum well(SPRINGER, 2012) Yesilgul, Unal; Ungan, Fatih; Sakiroglu, Serpil; Duque, Carlos; Mora-Ramos, Miguel; Kasapoglu, Esin; Sari, Huseyin; Sokmen, IsmailUsing a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga1-x In (x) N (y) As1-y /GaAs quantum well. Our calculations have revealed the dependence of impurity binding on the applied magnetic field, the impurity position, and the nitrogen and indium concentrations.Öğe Effect of the High-Frequency Laser Radiation on the Nonlinear Optical Properties of n-Type Double delta-Doped GaAs Quantum Wells(AMER SCIENTIFIC PUBLISHERS, 2019) Ungan, Fatih; Sari, Huseyin; Kasapoglu, Esin; Yesilgul, Unal; Sakiroglu, Serpil; Sokmen, IsmailIn the present work, the effect of non-resonant intense laser field on the nonlinear optical rectification and second and third harmonic generation of n-type double delta-doped GaAs quantum well is studied in detail. The energy eigenvalues and eigenfunctions of this structure are calculated within the framework of effective mass and envelope function approximations. Analytic formulas for the coefficients of nonlinear optical rectification and second and third harmonic generation are obtained using the compact-density matrix approach (CDMA) and iterative method. Based on this model, our obtained numerical results are reported as a function of incident photon energy for several values of non-resonant intense laser field. The results show that the coefficients of nonlinear optical rectification and second and third harmonic generation are strongly affected by the non-resonant intense laser field.Öğe Effects of an intense, high-frequency laser field on bound states in Ga1-xInxNyAs1-y/GaAs double quantum well(SPRINGER, 2012) Ungan, Fatih; Yesilgul, Unal; Sakiroglu, Serpil; Kasapoglu, Esin; Erol, Ayse; Arikan, Mehmet Cetin; Sari, Huseyin; Sokmen, IsmailWithin the envelope function approach and the effective-mass approximation, we have investigated theoretically the effect of an intense, high-frequency laser field on the bound states in a Ga (x) In1 - x N (y) As1 - y /GaAs double quantum well for different nitrogen and indium mole concentrations. The laser-dressed potential, bound states, and squared wave functions related to these bound states in Ga1 - x In (x) N (y) As1 - y /GaAs double quantum well are investigated as a function of the position and laser-dressing parameter. Our numerical results show that both intense laser field and nitrogen (indium) incorporation into the GaInNAs have strong influences on carrier localization.Öğe Effects of magnetic, electric, and non-resonant intense laser fields on exciton binding energy and exciton absorption in a symmetric Gaussian single quantum well(Springer Heidelberg, 2024) Kasapoglu, Esin; Yucel, M. B.The present study investigates the effects of external fields, including magnetic, electric, and non-resonant high-frequency intense laser fields, on the binding energies of the heavy hole excitons and the (hh1-e1) interband transitions from the ground state energy level of the heavy hole to the ground state energy level of the electron in GaAs/AlxGa1-xAs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text{GaAs}/{\text{Al}}_{x}{Ga}_{1-x}\text{As}$$\end{document} Gaussian type single quantum well. The study also considers the roles of the well width and the structure parameter. The results obtained show that the geometrical shape of the structure and the applied external fields are very effective tools on the excitonic binding and excitonic absorption spectra. From the results obtained, it was observed that the bandgap of semiconductor materials can be tuned by changing the structural parameters along with the applied external fields according to the purpose. This tunability enables the development of devices with optimized performance and new functionalities, thus driving innovation in various fields of technology.Öğe Effects of non-resonant intense laser, electric and magnetic fields on exciton binding energy and absorption spectra in the Gaussian double quantum well(Springer Heidelberg, 2024) Kasapoglu, EsinThe present study examines the impact of external fields, including electric, magnetic, and non-resonant high-frequency intense laser fields, on the binding energies of the heavy hole excitons and interband absorption in GaAs/AlxGa1-xAs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text{GaAs}/{\text{Al}}_{x}{\text{Ga}}_{1-x}\text{As}$$\end{document} Gaussian-shaped double quantum well. The study also considers the role of structural parameters such as the well width and the well depth. The results obtained show that the geometrical shape of the structure and the applied external fields are very effective tools on the excitonic binding and excitonic absorption spectra. From the results obtained, it was observed that the band gap of semiconductor materials can be changed by changing the structure parameters along with the external fields in accordance with the purpose. This tunability enables the development of devices with optimized performance and new functionalities, driving innovation in various fields of technology.Öğe Electron and donor-impurity-related Raman scattering and Raman gain in triangular quantum dots under an applied electric field(SPRINGER, 2016) Tiutiunnyk, Anton; Akimov, Volodymyr; Tulupenko, Viktor; Mora-Ramos, Miguel E.; Kasapoglu, Esin; Morales, Alvaro L.; Alberto Duque, CarlosThe differential cross-section of electron Raman scattering and the Raman gain are calculated and analysed in the case of prismatic quantum dots with equilateral triangle base shape. The study takes into account their dependencies on the size of the triangle, the influence of externally applied electric field as well as the presence of an ionized donor center located at the triangle's orthocenter. The calculations are made within the effective mass and parabolic band approximations, with a diagonalization scheme being applied to obtain the eigenfunctions and eigenvalues of the x-y Hamiltonian. The incident and secondary (scattered) radiation have been considered linearly-polarized along the y-direction, coinciding with the direction of the applied electric field. For the case with an impurity center, Raman scattering with the intermediate state energy below the initial state one has been found to show maximum differential cross-section more than by an order of magnitude bigger than that resulting from the scheme with lower intermediate state energy. The Raman gain has maximum magnitude around 35 nm dot size and electric field of 40 kV/cm for the case without impurity and at maximum considered values of the input parameters for the case with impurity. Values of Raman gain of the order of up to 10(4) cm(-1) are predicted in both cases.Öğe Inter-sub-band transitions and binding energies of donor impurities in a modulation-doped quantum well in the presence of electric field(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2009) Ungan, Fatih; Kasapoglu, Esin; Sari, Hueseyin; Soekmen, IsmailIn this study, we have investigated theoretically the effects of the electric field and doping concentration on the optical transitions in a modulation-doped GaAs-AlGaAs quantum well for different well widths. The binding energies of the donor have also been computed using a trial wave function with two parameters in the framework of an effective-mass approximation. The electronic structure of a modulation-doped quantum well under the electric field is determined by solving the Schrodinger and Poisson equations self-consistently in the effective-mass approximation. The results obtained show that inter-sub-band transitions and the energy levels in the modulation-doped quantum well can be significantly modified and controlled by the well width and donor concentration. The sensitivity to the well widths of the absorption coefficient can be used in various optical semiconductor devices' applications. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Non-resonant intense laser field and electric field effects on the optical characterization of Rosen-Morse quantum wells with different potential functions(Springer, 2024) Kasapoglu, EsinThe present study examines the electronic and optical properties of Rosen-Morse quantum wells, which exhibit hyperbolic and exponential potential profiles, subjected to intense laser fields and electric fields. Calculations are performed within the framework of the effective mass and parabolic band approximations. To determine the eigenvalues of electrons confined in these potentials, the diagonalization method was employed, utilizing orthonormal base functions that are solutions of an infinite square quantum well. To calculate the total absorption coefficient, including linear and nonlinear terms for transitions between the lowest two energy levels, a combination of the standard density matrix formalism and the perturbation expansion method was employed. Our results indicate that intense laser field is a valuable tool for controlling the confinement potential of low-dimensional systems, enabling the appropriate tuning of these systems. While the electric field applied only to symmetrical structures breaks the symmetry and causes the peaks in the absorption spectrum to shift to red, a blue shift of the absorption peaks was achieved with the combined effect of the selected geometric shapes of the quantum wells and the electric field. Therefore, it is hoped that the obtained results will provide important improvements in device applications with a suitable choice of both fields and structure parameters.Öğe Nonlinear optical properties of asymmetric n-type double delta-doped GaAs quantum well under intense laser field? (vol 90, 162, 2017)(SPRINGER, 2018) Sari, Huseyin; Kasapoglu, Esin; Yesilgul, Unal; Sakiroglu, Serpil; Ungan, Fatih; Sokmen, Ismail…Öğe Optical Absorption and Electroabsorption Related to Electronic and Single Dopant Transitions in Holey Elliptical GaAs Quantum Dots(WILEY-V C H VERLAG GMBH, 2018) Alejandro Vinasco, Juan; Alejandro Londono, Mauricio; Leon Restrepo, Ricardo; Eduardo Mora-Ramos, Miguel; Feddi, El Mustapha; Radu, Adrian; Kasapoglu, Esin; Luis Morales, Alvaro; Alberto Duque, CarlosThe electron states in a holey elliptically shaped GaAs quantum dot are investigated within the effective mass scheme with the use of the adiabatic approximation and the finite element method. The effects of a donor impurity center and an applied electric field are particularly taken into account. Electron-impurity energies are reported as functions of both the geometry of the quantum dot and the applied field intensity, whereas temperature effects are also included. The analysis of electron-impurity intersubband transitions allows the investigation of the light absorption response of the system.Öğe Parabolic-Gaussian Double Quantum Wells under a Nonresonant Intense Laser Field(Mdpi, 2023) Kasapoglu, Esin; Yucel, Melike Behiye; Duque, Carlos A.In this paper, we investigate the electronic and optical properties of an electron in both symmetric and asymmetric double quantum wells that consist of a harmonic potential with an internal Gaussian barrier under a nonresonant intense laser field. The electronic structure was obtained by using the two-dimensional diagonalization method. To calculate the linear and nonlinear absorption, and refractive index coefficients, a combination of the standard density matrix formalism and the perturbation expansion method was used. The obtained results show that the electronic and thereby optical properties of the considered parabolic-Gaussian double quantum wells could be adjusted to obtain a suitable response to specific aims with parameter alterations such as well and barrier width, well depth, barrier height, and interwell coupling, in addition to the applied nonresonant intense laser field.Öğe Simultaneous effects of the position dependent mass and magnetic field on quantum well with the improved Tietz potential(Elsevier, 2024) Kasapoglu, Esin; Yucel, Melike Behiye; Duque, Carlos A.; Mora-Ramos, MiguelE.In this study, we explored the synergistic impact of position -dependent mass and magnetic field on the electronic and optical properties of quantum wells, featuring an enhanced Tietz potential confinement incorporating both standard Morse and improved Rosen-Morse potentials, as influenced by variations in the structural parameter. Calculations were conducted within the framework of effective mass and parabolic band approximations. The diagonalization method was employed, selecting a wave function basis of trigonometric orthonormal functions to determine the eigenvalues and eigenfunctions of the confined electron potential. Our findings reveal that alterations in the sizes and shapes of the quantum wells, magnetic field strength, geometric asymmetry, and confinement parameters lead to significant variations in electron energies, transition between electron states, and the absorption spectrum. These outcomes offer valuable insights for investigating the electronic and structural properties of materials and devising novel materials with tailored optical characteristics.Öğe The roles of the magnetic field and impurities on the electronic and optical properties of the InAs quantum ring/dot(Elsevier, 2025) Shaer, Ayham; Deheliah, Diana; Kasapoglu, EsinThis work has explored the behavior of an electron traversing a two-dimensional InAs quantum ring, affected by an off-center impurity and exposed to a magnetic field. These investigations have involved analyzing the energy spectrum and determining both linear and non-linear absorption coefficients. To solve the Schrodinger equation of the system, the numerical diagonalization method was utilized by using by choosing orthonormal base functions that are solutions of two-dimensional isotropic harmonic oscillator. For the absorption coefficients including the linear and third-order nonlinear terms the standard density matrix formalism combined with the perturbation expansion method is used.
