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    Analysis of temperature dependent current-conduction mechanisms in Au/TiO2/n-4H-SiC (metal/insulator/semiconductor) type Schottky barrier diodes
    (American Institute of Physics Inc., 2014) Alialy, Sahar; Altındal, Şemsettin; Erbilen Tanrıkulu, Esra; Yıldız, Dilber Esra
    In order to determine the effective current-conduction mechanisms in Au/TiO2/n-4H-SiC (metal-insulator semiconductor) type Schottky barrier diodes (SBDs), their current-voltage (I-V) measurements were carried out in the temperature range of 200-380K. Some electrical parameters, such as ideality factor (n), zero-bias barrier height (BH) (?Bo), series and shunt resistances (Rs, Rsh), were obtained as 5.09, 0.81eV, 37.43 ?, and 435k? at 200K and 2.68, 0.95eV, 5.99 ?, and 73k? at 380K, respectively. The energy density distribution profile of surface states (Nss) was extracted from the forward-bias I-V data by taking into account voltage dependent of the ideality factor (nV), effective BH (?e), and Rs for 200, 300, and 380K. The Ln(I) vs V plots are completely parallel in the intermediate bias voltages, which may be well explained by field emission (FE) mechanism for each temperature. On the other hand, the high value of n cannot be explained with this mechanism. Therefore, to explain the change in BH and n with temperature, ?Bo vs q/2kT plot was drawn to obtain an evidence of a Gaussian distribution (GD) of the BHs and thus the mean value of BH (?? Bo) and standard deviation (?so) values were found from this plot as 1.396eV and 0.176V, respectively. The ??Bo and Richardson constant (A*) values were found as 1.393eV and 145.5A.cm-2 K-2 using modified Ln(Io/T 2)-(q2?s2/2k2T 2) vs q/kT plot, respectively. It is clear that all of the obtained main electrical parameters were found as a strong function of temperature. These results indicated that the current conduction mechanism in Au/TiO 2/n-4H-SiC (SBD) well obey the FE and GD mechanism rather than other mechanisms. © 2014 AIP Publishing LLC.
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    Öğe
    Study on the reverse bias carrier transport mechanism in Au/TiO2/n-4H-SiC structure
    (American Scientific Publishers, 2016) Alialy, Sahar; Yıldız, Dilber Esra; Altındal, Şemsettin
    In this paper we examine the reverse bias carrier transport mechanism in Au/TiO2/n-4H-SiC structure. The current-voltage-temperature (IR-V-T) plots have been investigated in the temperature range of 200-380 K. Experimental results indicated that IR-VR characteristics were found to be in agreement with the predicted characteristics, which are based on the Frenkel-Poole (FP) emission rather than Schottky emission (SE). According to FP theory, the main process in leakage current-transport is the emission of the electrons from a trapped states near the metal-semiconductor interface into a continuum of states which associated with each conductive dislocation. The obtained A(T) value versus q/kT plots were drawn and the barrier height (?t) which is necessary for electron emission from the trap was found at about 42 meV for low and 111 meV high temperatures, respectively. Copyright © 2016 by American Scientific Publishers.