Browsing by Author "Zeyrek, S."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Examination of Electrical and Dielectric Parameters of Au/n-Si Schottky Barrier Diodes (SBDs) with Organic Perylene Interlayer Using Impedance Measurements Under Various Illumination Intensities
    (Başkent Üniversitesi Sağlık Bilimleri Fakültesi, 2024-06-22) Bengi, S.; Cetinkaya, H. G.; Altindal, S.; Zeyrek, S.
    This study examines a metal-semiconductor structure with an organic perylene interlayer by measuring capacitance (C) and conductance (G/w) versus voltage under various lighting conditions and illumination levels (dark and 50-250 mW cm(-2)) in a wide range of voltage (+/- 5 V). The increase in illumination results in an increase in capacitance and conductance values in the depletion and accumulation regions due to surface-state illumination (N-ss). The barrier height (Phi(B)) decreased from 1.617 eV (in the dark) to 0.543 eV (under 250 mW cm(-2)). The C-V plot demonstrates peak behavior before going negative at the accumulation region. As the illumination intensity increases, the peak magnitude also increases, and concurrently, its position shifts towards the densely accumulated region due to the illumination-induced changes in surface states (N-ss) and the subsequent reordering/restructuring of these states. The lowest value of capacitance corresponds to the highest value of conductance, and the negative value of C decreases as illumination increases. The Hill-Coleman and Nicollian-Brews methods were used to obtain the voltage/illumination-dependent profile of N-ss and R-s, respectively. The relaxation mechanism of the SBD was also explained using electric modulus formalisms. The slope of ln(sigma(AC))-ln(P) plot changed from 0.474 and 0.824 and so Au/C20H12/n-Si SBD can be used in photonic applications.
  • No Thumbnail Available
    Item
    Temperature Dependence of Characteristic Parameters of The Au/C20H12/N-Si Schottky Barrier Diodes (SBDS) in The Wide Temperature Range
    (2017) Moraki, K.; Bengi, S.; Zeyrek, S.; Bulbul, M. M.; Altindal, S.; https://orcid.org/0000-0002-3348-0712; HPH-9613-2023
    Au/C20H12/n-Si SBD was fabricated and its characteristic parameters such as reverse-saturation current (I-o), ideality factor (n), zero-bias barrier height (I broken vertical bar(bo)), series and shunt resistances (R-s, R-sh) were found as 1.974 x 10(-7) A, 6.434, 0.351 eV, 30.22 a"broken vertical bar and 18.96 ka"broken vertical bar at 160 K and 1.061 x 10(-6) A, 2.34, 0.836 eV, 5.82 a"broken vertical bar and 24.52 ka"broken vertical bar at 380 K, respectively. While the value of n decreases with increasing temperature, I broken vertical bar(bo) increases. The change in I broken vertical bar(bo) with temperature is not agreement with negative temperature coefficient of forbidden band-gap of semiconductor (Si). Thus, I broken vertical bar (bo) versus n, I broken vertical bar (bo) and (n(-1) - 1) versus q/2kT plots were drawn to obtain an evidence of a Gaussian distribution (GD) of the BHs and all of them have a straight line. The mean value of BH () was found as 0.983 eV from the intercept of I broken vertical bar (bo) versus n plot (for n = 1). Also, the value of and standard deviation (sigma(s)) were found as 1.123 eV and 0.151 V from the slope and intercept of I broken vertical bar(bo) versus q/2kT plot. By using the modified Richardson plot, the and Richardson constant (A*) values were obtained as 1.116 eV and 113.44 A cm(-2) K-2 from the slope and intercept of this plot, respectively. It is clear that this value of A* (=113.44 A cm(-2) K-2) is very close to their theoretical value of 112 A cm(-2) K-2 for n-Si. In addition, the energy density distribution profile of surface states (D-it) was obtained from the forward bias I-V data by taking into account the bias dependent of the effective barrier height (I broken vertical bar (e) ) and ideality factor n(V) for four different temperatures (160, 200, 300, and 380 K). In conclusion, the I-V-T measurements of the Au/C20H12/n-Si SBD in the whole temperature range can be successfully explained on the basis of thermionic emission (TE) theory with GD of the BHs.