Yazar "Gullu, Omer" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Analysis of electrical and photoelectrical properties of ZnO/p-InP heterojunction
    (Elsevier Science Sa, 2011) Ocak, Yusuf Selim; Kulakci, Mustafa; Turan, Rasit; Kilicoglu, Tahsin; Gullu, Omer
    AZnO/p-InP heterojunction has been fabricated by dc sputtering of ZnO on p-InP. It has been observed that the device has a good rectification. The electrical properties of the device such as ideality factor, barrier height, series resistance have been calculated using its current-voltage (I-V) measurements between 300 and 380K with 20K intervals. The short current density (J(sc)) and open circuit voltage (V-oc) parameters have been determined between 40 and 100mW/cm(2). The photovoltaic parameters of the device have been also determined under 100mW/cm(2) and AM1.5 illumination condition. (C) 2011 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    THE CHARACTERISTIC DIODE PARAMETERS IN Ti/p-InP CONTACTS PREPARED BY DC SPUTTERING AND EVAPORATION PROCESSES OVER A WIDE MEASUREMENT TEMPERATURE
    (World Scientific Publ Co Pte Ltd, 2017) Ejderha, Kadir; Asubay, Sezai; Yildirim, Nezir; Gullu, Omer; Turut, Abdulmecit; Abay, Bahattin
    The titanium/p-indium phosphide (Ti/p-InP) Schottky diodes (SDs) have been prepared by thermal evaporation and DC magnetron sputtering deposition. Then, their current-voltage (I-V) characteristics have been measured in the sample temperature range of 100-400K with steps of 20 K. The characteristic parameters of both Ti/ p-InP SDs have been compared with each other. The barrier height (BH) values of 0.824 and 0.847 at 300K have been obtained for the sputtered and the evaporated SDs, respectively. This low BH value for the sputtered SD has been attributed to some defects introduced by the sputtered deposition technique over a limited depth in to the p-type substrate. The BH of the evaporated and sputtered diodes has decreased with the standard deviations of 58 and 64mV obeying to double-Gaussian distribution (GD) in 220-400K range, respectively, and it has seen a more sharper reduction for the BHs with the standard deviations of 93 and 106 mV in 100-220K range. The Richardson constant values of 89.72 and 53.24 A(Kcm)(-2) (in 220-400K range) for the evaporated and sputtered samples, respectively, were calculated from the modiified ln(I-0/T-2) - q(2)sigma(2)(s)/2k(2)T(2) vs (kT)(-1) curves by GD of the BHs. The value 53.24A (Kcm)(-2) for the sputtered sample in high temperatures range is almost the same as the known Richardson constant value of 60 A(Kcm)(-2) for p-type InP.
  • [ X ]
    Öğe
    Temperature-dependent behavior of Ti/p-InP/ZnAu schottky barrier diodes
    (Iop Publishing Ltd, 2008) Asubay, Sezai; Gullu, Omer; Abay, Bahattin; Turut, Abdulmecit; Yilmaz, Ali
    The current-voltage ( I-V) characteristics of Ti/p-InP Schottky diodes have been measured in a wide temperature range with a temperature step of 20 K. An experimental barrier height ( BH) Phi(ap) value of about 0.85 eV was obtained for the Ti/p-InP Schottky diode at 300 K. A decrease in the experimental BH Phi(ap) and an increase in the ideality factor n with a decrease in temperature have been explained on the basis of a thermionic emission mechanism with the Gaussian distribution of the barrier heights due to the BH inhomogeneities at the metal semiconductor interface. (Phi) over bar (b) and A* as 1.01 eV, and 138 A cm(-2) K-2, respectively, have been calculated from a modified ln( I-0/T-2) - q(2)sigma(2)(s)/2k(2)T(2) versus 1/T plot. This BH value is in close agreement with the values of 0.99 eV obtained from the Phi(ap) versus 1/T and ln( I-0/T-2) versus 1/nT plots.