Yazar "Ozkapi, Sena Guler" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    Calculation of Intradonor Normalized Transition Energy in Spherical Quantum Dots Made of Different Materials
    (Wiley-V C H Verlag Gmbh, 2023) Mese, Ali Ihsan; Cicek, Engin; Ozkapi, Sena Guler; Ozkapi, Baris; Erdogan, Ilhan
    Under the effective mass approximation, the binding energies, transition energies between 1s and 1p states, and normalized transition energies of spherical quantum dots made of different materials are calculated using the variational method. In particular, binding, transition, and normalized transition energies are examined depending on the radius of the quantum dot and the position of the hydrogenic impurity. It is observed that the binding energy and transition energy decrease as the radius of the quantum dot increases, whereas the normalized transition energy increases. In all four different structures, it is seen that the binding energy first reaches a maximum and then starts to decrease according to the position of the hydrogenic impurity. In contrast, the transition energy behaves almost the opposite. Additionally, when the change of the normalized transition energy is examined according to the impurity position, it is determined that it decreases up to the value of r(i)/R = 0.6 and then remains almost constant. According to our literature review, the normalized transition energy for the four different quantum dots is calculated for the first time in this study.
  • Küçük Resim Yok
    Öğe
    Effect of Si and Ge doping on electronic structure of InP nanowire
    (Natl Inst Optoelectronics, 2023) Ozkapi, Sena Guler; Ozkapi, Baris; Mese, Ali Ihsan; Erdogan, Ilhan
    We present a study on the effect of Si and Ge doping on the electronic and atomic structure of Indium Phosphide nanowires using first principles calculations. Hydrogen passivated InP nanowires in zinc blende structure with 1.5 nanometers diameter [111] growth direction are considered. The results show that the substitutional Si and Ge dopings narrow the band gap of InP nanowires, and these nanowires are direct band gap semiconductors. The Si doping shifts the VBM and CBM to the lower energy levels, and this energy decrease is less in the Ge doped nanowire. PDOS analyses show that VBM and CBM occur mainly from the p orbitals of the In and P atoms. Electronic states at the Fermi level for doped nanowires are compatible with the donor levels that appear in the band structure.
  • Küçük Resim Yok
    Öğe
    Electronic band structures of Te-doped GaN nanowires
    (Elsevier Science Bv, 2017) Ozkisi, Harun; Ozkapi, Baris; Ozkapi, Sena Guler; Dalgic, Seyfettin
    In this study, we investigate electronic band structures of Te-doped GaN nanowires with three different radii using the first principles methods, which is based on the density functional theory. The relaxed structures, total energies and electronic band structures of pure and Te-doped GaN nanowires are calculated. The results show that the energy band gap values reduce when GaN nanowires are doped with a Te atom. While the band gap values of pure GaN nanowires increase with increasing nanowire radius, they present a decrease for Te-doped GaN nanowires. (C) 2016 Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
    Öğe
    First principles study on the electronic properties of BN nanowires
    (Elsevier Science Bv, 2017) Ozkapi, Sena Guler; Ozkapi, Baris; Ozkisi, Harun; Dalgic, Seyfettin
    The electronic and structural properties of BN nanowires are studied by using first principles calculations based on density functional theory. In order to understand dependence of the electronic band structures and density of states on nanowire diameters and shapes, we consider BN nanowires with various diameters in the [001] growth direction. Our results reveal that the effect of changing diameter on electronic properties plays an important role and the band gap can be tuned by changing the wire diameter. (C) 2016 Elsevier Ltd. All rights reserved.