Yazar "Erdal, M. O." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim
    Öğe
    The effect of indium doping concentration on the electrical and dielectric properties of Al/In:ZnO/p-Si heterojunctions
    (ELSEVIER, 2019) Yıldırım, M.; Erdal, M. O.; Kocyigit, A.
    Undoped and 0.1% 0.5% and 1.0% indium doped ZnO thin films were obtained by spin coating method as interfacial thin film layer between Al metal and p-Si semiconductor to investigate dielectric properties of the Al/In: ZnO/p-Si heterojunctions. Impedance spectroscopy technique was employed to characterize the dielectric properties of the Al/In: ZnO/p-Si heterojunctions depending on frequency (from 10 kHz to 1 MHz) and voltage (from - 5 V to + 5 V). The results imparted that interface states (N-ss), series resistance (R-s), barrier height (Phi(b)) and the concentration of acceptor atoms (N-a) influenced frequency changes. The dielectric parameters such as dielectric constant (epsilon'), dielectric loss (epsilon ''), loss tangent (tan delta), real and imaginary parts of the electric modulus (M' and M '') and ac electrical conductivity (sigma) values were calculated from impedance spectroscopy measurements and discussed in details for changing frequency and voltage for various In doped ZnO thin film interlayers. The dielectric properties of the Al/In:ZnO/p-Si heterojunctions were affected both In doping concentration and the frequency and voltage changes. The Al/In:ZnO/p-Si heterojunctions can be considered for industrial applications to increase the control.
  • Küçük Resim Yok
    Öğe
    The rate of Cu doped TiO2 interlayer effects on the electrical characteristics of Al/Cu:TiO2/n-Si (MOS) capacitors depend on frequency and voltage
    (PERGAMON-ELSEVIER SCIENCE LTD, 2020) Erdal, M. O.; Kocyigit, A.; Yildirim, M.
    In order to determine the surface states (N-ss), series resistance (R-s), and (Cu:TiO2) interlayer effects on the electrical characteristics of the Al/Cu:TiO2/n-Si metal oxide semiconductor (MOS) capacitors, both capacitance (C) and conductance (G) values were measured for frequency ranges of 10 kHz-1 MHz and +/- 5 V voltage ranges. In addition, to know Cu doping concentration effect on the MOS capacitor, the Al/Cu:TiO2/n-Si was fabricated with various rates Cu:TiO2 interlayer (5, 10, 15%) grown on n-Si susbtrate by spin-coating. The increase in capacitance via decreasing frequencies was attributed to the existence of N-ss and their relaxation time. The frequency dependent diffusion potential (V-d), doping of donor atoms (N-d), Fermi energy (E-F), barrier height (Phi b) and depletion layer width (W-d) values were extracted from the linear part of reverse bias C-2-V curves. While the value the R-s decreased with increasing frequency, the N-ss values increased for the three MOS capacitors. The profiles of N-ss and R-s depending on voltage were also plotted by Nicollian-Brews methods and using high-low frequency (C-HF-C-LF) capacitance, respectively. The mean values of N-ss for three capacitors were found at about 10(12) eV(-1)cm(-2) as suitable electronic devices. The lower values of the N-ss can be attributed to passivation effect of Cu:TiO2 interlayer.
  • Küçük Resim
    Öğe
    Synthesis and Properties of Boron Doped NaxCo2O4 Nanocrystalline Ceramics
    (SPRINGER, 2012) Uslu, I.; Cetin, Saime Sebnem; Aytimur, A.; Yuceyurt, S.; Erdal, M. O.
    Sodium cobalt oxide (NaCo2O4) nanofibers with diameters ranging between 20 and 200 nm were prepared by electrospinning a precursor mixture of PVA/(Na-Co) acetate. This was the first time any such attempt was made. Afterwards, the electrospun nanofibers were subjected to calcination treatment. The characteristics of the fibers were investigated using a Fourier transform infrared spectroscopy, a X-ray diffractometer, and a scanning electron microscopy. The boron doped and undoped NaCo2O4 nanofibers calcined at 850 A degrees C were polycrystalline of the gamma NaxCo2O4 phase having diameters ranging between 20 and 60 nm with grain sizes of 5-10 nm, and the nanofibers calcined at 800 A degrees C were single crystals having linked particles or crystallites with particle sizes ranging between 60 and 200 nm. The results indicated a significant effect of calcination temperature on the crystalline phase and morphology of the nanofibers. It could be seen in the SEM micrograph of the fibers that when boron was added, this resulted in the formation of cross-linked bright-surfaced fibers. The average fiber diameter for boron doped and undoped fiber mats were 204 and 123 nm, respectively. The grain diameters of boron doped and undoped nanocrystalline sintered powders were measured as 140 and 118 nm, respectively.