Yazar "Kandaz, Mehmet" seçeneğine göre listele

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  • Küçük Resim
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    A Comparative Study on the Main Electrical Parameters of Au/n-Si, Au/Biphenyl-CuPc/n-Si/ and Au/Biphenylsubs-CoPc/n-Si/ Type Schottky Barrier Diodes
    (Amer Scientific Publishers, 2016) Demir, Ahmet; Yücedağ, İbrahim; Ersöz, Gülçin; Altındal, Şemsettin; Baraz, Nalan; Kandaz, Mehmet
    We have produced Au/n-Si (MS), Au/n-Si/biphenyl-CuPc (MPS1), and Au/n-Si/biphenylSubs-CoPc (MPS2) type Schottky barrier diodes (SBDs) to investigate the effect of interfacial layer on the main electrical parameters. Biphenyl-CuPc and biphenylSubs-CoPc interfacial layers were successfully coated on n-Si substrate by using the spin coating system. The current-voltage (I-V) characteristics of these structures were investigated at room temperature and they were considerably influenced by the interfacial layer. The main electronic parameters of these three type diodes that are reverse saturation current (I-0), series resistance (R-s), ideality factor (n), and zero-bias barrier height (Phi(B0)) were determined from the forward bias I-V characteristic. The energy density distribution profile of the interface states (N-ss) was also obtained from the forward I-V data by taking into account voltage dependent effective barrier height (Phi(theta)) and ideality factor n(V), and increased from the bottom of conductance band to the mid-gap energy of Si almost exponentially. In addition, the voltage dependent profile of resistance was obtained from capacitance-voltage (C-V) and conductance-voltage (G/omega - V) data at high frequency (500 kHz) at room temperature for each diode. Experimental results show that the R-s, N-ss and the interfacial layer are significantly effective on the electrical characteristics.
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    Controlling the electrical characteristics of Au/n-Si structure with and without (biphenyl-CoPc) and (OHSubs-ZnPc) interfacial layers at room temperature
    (Wiley, 2017) Baraz, Nalan; Yücedağ, İbrahim; Demir, Ahmet; Demir, Gülçin Ersöz; Altındal, Şemsettin; Kandaz, Mehmet
    In order to interpret well whether or not the organic or polymer interfacial layer is effective on performance of the conventional Au/n-Si (metal semiconductor [MS]) type Schottky barrier diodes (SBDs), in respect to ideality factor (n), leakage current, rectifying rate (RR), series and shunt resistances (R-s, R-sh) and surface states (N-ss) at room temperature, both Au/biphenyl-CoPc/n-Si (MPS1) and Au/OHSubs-ZnPc/n-Si (MPS2) type SBDs were fabricated. The electrical characteristics of these devices have been investigated and compared by using forward and reverse bias current-voltage (I-V) characteristics in the voltage range of (-4V)-(4V) for with and without (biphenyl-CoPc) and (OHSubs-ZnPc) interfacial layers at room temperature. The main electrical parameters of these diodes such as reverse saturation current (I-0), ideality factor (n), zero-bias barrier height (phi(B0)), RR, R-s and R-sh were found as 1.14x10(-5)A, 5.8, 0.6eV, 362, 44 and 15.9k for reference sample (MS), 7.05x10(-10)A, 3.8, 0.84eV, 2360, 115 and 270k for MPS1 and 2.16x10(-7)A, 4.8, 0.7eV, 3903, 62 and 242k for MPS2, respectively. It is clear that all of these parameters considerably change by using an organic interfacial layer. The energy density distribution profile of N-ss was found for each sample by taking into account the voltage dependence of effective barrier height (phi(e)) and ideality factor, and they were compared. Experimental results confirmed that the use of biphenyl-CoPc and OHSubs-ZnPc interfacial layer has led to an important increase in the performance of the conventional of MS type SBD. Copyright (c) 2015 John Wiley & Sons, Ltd.
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    Nonperipheral tetra phthalocyanines bearing alkyl chain moiety; Synthesis, characterization and fabrication of the OFET based on phthalocyanine
    (Elsevier Science Sa, 2015) Bilgiçli, Ahmet T.; Yaraşır, Meryem N.; Kandaz, Mehmet; İlik, Cihat; Demir, Ahmet; Bağcı, Sadık
    In this study, the novel tetra nonperipherally alpha-substituted 1(4), 8(11), 15(18), 22(25)-tetrakis undecyloxy phthalocyanine derivatives bearing 1-dodecanol moiety, M{Pc[O-(CH2)(11)CH3)](4) (M=Co(2), Zn(3), Cu(4), Mn(5))}, (Pc: Phthalocyanine) have been synthesized for the first time and their structures characterized by using H-1 NMR, C-13 NMR, FT-IR, MALDI-TOF/MS, UV-vis spectral and elemental analysis. Also Surface morphology of phthalocyanine complexes were investigated by atomic force microscope (AFM) as complementary technic. The new synthesized complexes are soluble in both polar solvents, such as THF and DMF, and nonpolar solvents such as CHCl3, CH2Cl2, benzene and hexane. An organic thin film transistor (OTFT) or organic field effect transistor (OFET), based on novel cobalt phthalocyanine (CoPc) was fabricated with SiO2 as the gate dielectric material. We have also investigated electrical characterization of the OTFT of the new synthesis CoPc layer and composite semiconductor material. While Au was deposited as gate contact, source and drain contacts of the device were coated with Ag by using thermal evaporation method. CoPc layer was prepared with spin coater method. Our study has shown that the new synthesis CoPc make a noteworthy on the OTFT. The CoPc OTFT exhibited saturation at the order of mu(FET) of 2,01 x 10(-1) cm(2)/V s. I-on/I-off and V-T of this device are 2 x 10(2) and -2,25 V, respectively. (C) 2015 Elsevier B.V. All rights reserved.