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  • Küçük Resim
    Öğe
    The analysis of the electrical characteristics and interface state densities of Re/n-type Si Schottky barrier diodes at room temperature
    (TAYLOR & FRANCIS LTD, 2019) Durmuş, Haziret.; Karataş, Şükrü.
    The main electrical characteristics of current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature of the Re/n-type Si Schottky barrier diodes prepared by pulsed laser deposition (PLD) method have been examined. The values of the basic electrical properties such as forward saturation current (I-o), ideality factors (n), barrier heights (?(bo)), rectification ratio (RR) and series resistances (R-S) were obtained from I-V and C-V measurements using different calculation methods. At low voltages (V0.3V), the electrical conduction was formed to take place by thermionic emission, whereas at high voltages (V>0.3V), a space charge limited conduction mechanism was shown. Furthermore, the interface state densities (N-SS) as a function of energy distribution (E-SS- E-V) was obtained from the I-Vdata by taking into account the bias dependence of the effective barrier height (phi(b)) for the Re/n-type Si Schottky barrier diodes.
  • Küçük Resim
    Öğe
    Identifying of series resistance and interface states on rhenium/n-GaAs structures using C-V-T and G/?-V-T characteristics in frequency ranged 50 kHz to 5 MHz
    (SPRINGER, 2020) Çiçek, Osman.; Durmuş, Haziret.; Altındal, Şemsettin.
    In this study, Re/n-GaAs with a native oxide layer based on metal-semiconductor (MS) structures were produced and then, the capacitance-voltage-temperature (C-V-T) and the conductance-voltage-temperature (G/-V-T) data of them were obtained in the frequency ranged 50 kHz to 5 MHz. Using the raw data, the electronic parameters was calculated by the developed LabVIEW-based program. Methodologically, the series resistance (R-s) values were calculated from the measured capacitance (C-m) and conductivity (G(m)) values, while the interface state (N-ss) values were obtained from using the combined high (C-HF)-low (C-LF) frequency capacitance method by Nicollian and Brews. Experimentally, the C values increased with a decreasing frequency, while decreased with increasing temperatures in the depletion and accumulation regions. On the other hand, G/ values decreased with increasing frequency in forward and reverse bias regions. It can be attributed that, the C and the G/ values are quite affected by the presence of the R-s and the N-ss in the forbidden energy gap and a native oxide layer between M and S. The R-s-V-T curves have especially peaks in accumulation and depletion regions at low frequency values, whereas these peaks decreased at high frequencies. In addition, the N-ss-V-T curves give peaks in the range of - 0.1 V to 0.7 V at variable temperatures and the N-ss values decrease with increasing temperature and shift towards negative bias regions. Experimental results indicate that the R-s and N-ss are important parameters and so, these parameters must be considered in sensor applications based on Re/n-GaAs structures.
  • Küçük Resim
    Öğe
    On the possible conduction mechanisms in Rhenium/n-GaAs Schottky barrier diodes fabricated by pulsed laser deposition in temperature range of 60-400K
    (SPRINGER, 2019) Durmuş, Haziret.; Yıldırım, Mert.; Altındal, Şemsettin.
    AbstarctThis study presents electrical characteristics of n-GaAs based Schottky barrier diodes (SBDs) with Rhenium (Re) rectifier contacts. The electrical characteristics of the Re/n-GaAs SBDs were investigated utilizing the forward bias current-voltage (I-F-V-F) data collected in temperature range of 60-400K. The values of ideality factor (n) and zero-bias barrier height (phi(Bo)) were found as 9.10 and 0.11eV for 60K, and 1.384 and 0.624eV for 400K, respectively, on the basis of thermionic-emission theory. The conventional Richardson plot deviated from linearity at low temperatures and the Richardson constant value (A(*)) was obtained quite lower than the theoretical value for this semiconductor (8.16Acm(-2)K(-2)). nkT/q-kT/q plot shows that the field-emission may be dominant mechanism at low temperatures as a result of tunneling via surface states since the studied n-GaAs's doping concentration is on the order of 10(18) cm(-3), i.e. at high values so leads to tunneling. On the other hand, phi(Bo)-n, phi(Bo)-q/2kT and (n(-1)-1)-q/2kT plots exhibit linearity but this linearity is observed for two temperature regions (60-160K and 180-400K) due the presence of double Gaussian distribution (GD) of the barrier height. Therefore, the standard deviation value was obtained from the plot of phi(Bo)-q/2kT and it was used for modifying the conventional Richardson plot into the modified Richardson plot by which the values of mean barrier height and A(*) were obtained as 0.386eV and 15.55Acm(-2)K(-2) and 0.878eV and 8.35Acm(-2)K(-2) for the low and high temperature regions, respectively. As a result, I-F-V-F-T characteristics of the Re/n-GaAs SBDs were successfully elucidated by double-GD of barrier height.