Browsing by Author "Cetinkaya, H. G."

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Investigation Of The Frequency Effect On Electrical Modulus And Dielectric Properties Of Al/P-Si Structure With %0.5 Bi:Zno Interfacial Layer
(Başkent Üniversitesi Teknik Bilimler Meslek Yüksekokulu, 2024-05-01) Bengi, S.; Cetinkaya, H. G.; Altindal, S.; Durmus, P.
Capacitance and conductance measurements were made to evaluate the effects of voltage and frequency on the dielectric properties, ac electrical conductivity (sigma(ac)), and electric-modulus of the Al/%0.5 Bi:ZnO/p-Si structures. The measurements were taken in a voltage range of (- 4 V)-(+ 4 V) and frequency range of 0.1-1 MHz, respectively. All parameters were discovered to have substantial relationships to voltage and frequency at accumulation and depletion regions due to relaxation mechanisms and interface traps positioned between %0.5 Bi:ZnO interlayer and p-Si with energies in the Si bandgap. The e'-V, M''-V, and Z''-V plots all demonstrate a peak, and because of electronic charges being reordering and restructuring at surfaces, traps, and dipole-polarization under the external electric field, the peak's position and magnitude vary with frequency. The double logarithmic sigma ac-w curve shows linear behaviour, its slope was found as 0.699, and this value of the Al/%0.5 Bi:ZnO/p-Si/Au structure has high ac conductivity or low resistivity. The observed high changes in the dielectric constant and dielectric loss (e', e'') were explained by Maxwell-Wagner type polarization as well as interface traps.
The Capacitance/Conductance And Surface State Intensity Characteristics Of The Al/(CMAT)/p-Si Structures
(PHYSICA SCRIPTA, 2024-01-24) Cetinkaya, H. G.; Bengi, S.; Sevgili, O.; Altindal, S.
To determine the Al/(CMAT)/p-Si structure's admittance analysis, capacitance/conductance versus frequency (C/G-V-f) data was obtained in the 3 kHz-3 MHz and -2/4 V ranges at room temperature. The powder form of CeMgAl11O19: Tb (CMAT) was thermally evaporated onto the front of p-Si wafer at 10-6 Torr as interfacial layer. From the Nicollian and Brews method, voltage-dependent spectra of Rs were derived for various frequencies. The parallel conductance and low-high frequency capacitance (CLF-CHF) techniques, respectively, were used to determine the voltage and frequency dependent spectra of Nss and their lifetime (tau). Surface states (Nss), which are identified by admittance measurements, emerge at the M/S interlayer because of high capacitance and conductance values at low frequencies. This can also be explained by the Nss's ability to track ac signals well at lower frequencies. The normalized parallel conductance versus frequency (Gp/omega-f) plot under various biases shows a peak because of Nss existence. x-ray diffractometer (XRD) was used for structural investigation and the average crystal size (D) of the nanocrystals (CMAT) was found to be less than 0.34 nm by using the Debye-Scherer's equation.
The Capacitance/Conductance And Surface State Intensity Characteristics Of The Al/(Cmat)/P-Si Structures
(Başkent Üniversitesi Fen Edebiyat Fakültesi, 2024-02-01) Cetinkaya, H. G.; Bengi, S.; Sevgili, O.; Altindal, S.
To determine the Al/(CMAT)/p-Si structure's admittance analysis, capacitance/conductance versus frequency (C/G-V-f) data was obtained in the 3 kHz-3 MHz and -2/4 V ranges at room temperature. The powder form of CeMgAl11O19: Tb (CMAT) was thermally evaporated onto the front of p-Si wafer at 10-6 Torr as interfacial layer. From the Nicollian and Brews method, voltage-dependent spectra of Rs were derived for various frequencies. The parallel conductance and low-high frequency capacitance (CLF-CHF) techniques, respectively, were used to determine the voltage and frequency dependent spectra of Nss and their lifetime (tau). Surface states (Nss), which are identified by admittance measurements, emerge at the M/S interlayer because of high capacitance and conductance values at low frequencies. This can also be explained by the Nss's ability to track ac signals well at lower frequencies. The normalized parallel conductance versus frequency (Gp/omega-f) plot under various biases shows a peak because of Nss existence. x-ray diffractometer (XRD) was used for structural investigation and the average crystal size (D) of the nanocrystals (CMAT) was found to be less than 0.34 nm by using the Debye-Scherer's equation.
The Frequency Dependent of Main Electrical Parameters, Conductivity and Surface States in the Al/ (%0.5 Bi:ZnO)/p-Si/Au (MIS) Structures
(Başkent Üniversitesi Teknik Bilimler Meslek Yüksek Okulu, 2024-03-09) Cetinkaya, H. G.; Bengi, S.; Durmus, P.; Demirezen, S.; Altindal, S.
The capacitance/conductance-voltage-frequency (C/G-V-f) features of the Au/p-Si structures with (%0.5 Bi-doped ZnO) interlayer grown by spin-coating technique was investigated between 100 kHz and 1 MHz. The C-2-V curves that depend on frequency were used to determine the electrical-parameters like diffusion-potential (V-D), Fermi-energy level (E-F), barrier-height (Phi(B)), and depletion-layer (W-D) thickness. The value of Phi(B) was found to increase with increasing frequency due to the decrease in surface-states (N-ss) effects on the C-V characteristics. Voltage dependent series-resistance (R-s) was obtained by using Nicollian-Brews method for each frequency and it decreased with increasing frequency. Both the low-high frequency capacitance (C-LF-C-HF) and Hill-Coleman techniques were used to determine the voltage-dependent profile of N-ss. While N-ss decreases with increasing frequency, voltage-dependent on them give two distinctive peaks due to a special distribution of them at interlayer/semiconductor interface in the bandgap depending on their relaxation time. All these experimental results indicate that the existence of R-s, N-ss, and interlayers considerably influence the impedance measurements.