Investigation of negative dielectric constant in Au/1 % graphene (GP) doped-Ca1.9Pr0.1Co4Ox/n-Si structures at forward biases using impedance spectroscopy analysis

Çetinkaya, H.G.; Alialy, S.; Altındal, Ş.; Kaya, A.; Uslu, İbrahım

doi:10.1007/s10854-015-2816-7

Cited by 25 publications

(7 citation statements)

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“…The ε , ε , tan δ, σ ac , M and M parameters were calculated using C and Gdata for Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures by using the following expressions [7,22,[26][27][28][29][30][31]:…”

Section: Resultsmentioning

confidence: 99%

A comparative study on dielectric behaviours of Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures with different interlayer thicknesses using impedance spectroscopy methods

et al. 2018

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Three different thicknesses (50, 150 and 500 nm) Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC wafer as interlayer by electrospinning method and so, Au/(Zn-doped PVA)/n-4H-SiC metal-polymer-semiconductor structures were fabricated. The thickness effect of Zn-doped PVA on the dielectric constant (ε), dielectric loss (ε), losstangent (tan δ), real and imaginary parts of electric modulus (M and M) and ac electrical conductivity (σ ac) of them were analysed and compared using experimental capacitance (C) and conductance (G/ω) data in the frequency range of 1-500 kHz at room temperature. According to these results, the values of ε and ε decrease with increasing frequency almost exponentially, σ ac increases especially, at high frequencies. The M and M values were obtained from the ε and ε data and the M and M vs. f plots were drawn for these structures. While the values of ε , ε and tan δ increase with increasing interlayer thickness, the values of M and M decrease with increasing interlayer thickness. The double logarithmic σ ac vs. f plots for each structure have two distinct linear regimes with different slopes, which correspond to low and high frequencies, respectively, and it is prominent that there exist two different conduction mechanisms. Obtained results were found as a strong function of frequency and interlayer thickness.

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Section: Resultsmentioning

confidence: 99%

A comparative study on dielectric behaviours of Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures with different interlayer thicknesses using impedance spectroscopy methods

et al. 2018

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“…Such behavior in Μ ′ and Μ ″ with frequency can be attributed to the polarization . However, the value reaches a maximum at high frequencies for each applied forward bias voltage corresponding to M ∞ = 1/ε′ ∞ , due to relaxation processes . In other words, both Μ ' and Μ ″ approach almost to zero at low frequencies.…”

Section: Resultsmentioning

confidence: 93%

“…As a result, it can be said that the peak behavior in M and tanδ, both, or the change in them with frequency indicates that the structure exhibits relaxation phenomena . Moreover, especially in narrow‐forbidden bandgap semiconductor, the charge carriers are not sufficiently free to move, but they can be trapped and so this causes a polarization . On the other hand, as can be seen in Figure (a), the value of ε′ starts to decrease rapidly at high frequencies since space charge polarization weakens.…”

Section: Resultsmentioning

confidence: 97%

“…The frequency‐dependent total electrical conductivity (σ) of the MPS structure was also obtained from the following equation for 1 V at room temperature and it is shown in Figure .

σ (ω) = true(\frac{d}{A} true) ω C \tan δ = {ε ″ ω ε}_{0} = σ_{d c} + A ω^{n}

where, σ dc is the dc conductivity corresponding to low frequencies, σ ac is the ac conductivity corresponding to the high frequencies (Figure ), A is a constant of proportionality depended on frequency, and ω is angular frequency (=2π f or 2π/ T ).…”

Section: Resultsmentioning

confidence: 99%

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Frequency and voltage dependence of dielectric properties, complex electric modulus, and electrical conductivity in Au/7% graphene doped‐PVA/n‐Si (MPS) structures

Yerişkin

Balbaşı

Tataroğlu

2016

J of Applied Polymer Sci

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In order to increase the capacitance of Au/n-Si (MS) structure, 7% graphene doped PVA was coated on n-Si as an interfacial layer. The measured data of capacitance (C) and conductance (G/x) of Au/7% graphene doped-PVA/n-Si (MPS) structure was utilized for the calculation of real and imaginary parts of complex permittivity (e* 5 e 0 2 je 00 ), loss tangent (tand), complex electric modulus (M* 5 M 0 1 jM 00 ), and electrical conductivity (r). The admittance measurements (C and G/x) were carried out in the frequency range of 0.5 kHz to 1 MHz at room temperature. Frequency dependence of the dielectric constant (e 0 ), dielectric loss (e 00 ) and tand shows a dispersive behavior at low frequencies. This behavior was explained by Maxwell-Wagner relaxation. Due to the dipolar and the interfacial polarizations, as well as the surface states (N ss ) and the interfacial PVA layer, the parameters exhibited a strong dependence on frequency and applied bias voltage. The r versus log(f) plot exhibited both low and high frequency dispersion phenomena such that at low frequencies r value corresponding to the dc conductivity (r dc ), but at high frequencies it corresponds to the ac conductivity (r ac ). M 0 and M 00 , both, have low values in the low frequency region. However, an increase is observed with the increasing frequency due to the short-range mobility of charge carriers. As a result, the change in dielectric parameters and electric modulus with frequency is the result of relaxation phenomena and surface states.

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“…The negative region of capacitance widened from 1.03 GHz to 1.80 GHz to become 6.90 MHz to 1.80 GHz when the biasing direct current (dc) voltage was increased to 5.0 V. The negative capacitance effect is reported to be caused by injection of minority carriers (tunneling) when the device is forward biased. 3,19 Negative capacitance can be employed to change the signal properties of resonant electronic circuits such as time-based sensor interfaces to control the oscillation with enhanced tuning. It can also be used to increase the tuning range of voltage-controlled oscillators.…”

Section: Resultsmentioning

confidence: 99%

Physical Design and Dynamical Analysis of Resonant–Antiresonant Ag/MgO/GaSe/Al Optoelectronic Microwave Devices

Kmail

Qasrawi

2015

Journal of Elec Materi

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In this work, the design and optical and electrical properties of MgO/GaSe heterojunction devices are reported and discussed. The device was designed using 0.4-lm-thick n-type GaSe as substrate for a 1.6-lm-thick p-type MgO optoelectronic window. The device was characterized by means of ultravioletvisible optical spectrophotometry in the wavelength region from 200 nm to 1100 nm, current-voltage (I-V) characteristics, impedance spectroscopy in the range from 1.0 MHz to 1.8 GHz, and microwave amplitude spectroscopy in the frequency range from 1.0 MHz to 3.0 GHz. Optical analysis of the MgO/GaSe heterojunction revealed enhanced absorbing ability of the GaSe below 2.90 eV with an energy bandgap shift from 2.10 eV for the GaSe substrate to 1.90 eV for the heterojunction design. On the other hand, analysis of I-V characteristics revealed a tunneling-type device conducting current by electric fieldassisted tunneling of charged particles through a barrier with height of 0.81 eV and depletion region width of 670 nm and 116 nm when forward and reverse biased, respectively. Very interesting features of the device are observed when subjected to alternating current (ac) signal analysis. In particular, the device exhibited resonance-antiresonance behavior and negative capacitance characteristics near 1.0 GHz. The device quality factor was $10 2 . In addition, when a small ac signal of Bluetooth amplitude (0.0 dBm) was imposed between the device terminals, the power spectra of the device displayed tunable band-stop filter characteristics with maximum notch frequency of 1.6 GHz. The energy bandgap discontinuity, the resonance-antiresonance behavior, the negative capacitance features, and the tunability of the electromagnetic power spectra at microwave frequencies nominate the Ag/MgO/ GaSe/Al device as a promising optoelectronic device for use in multipurpose operations at microwave frequencies.

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Investigation of negative dielectric constant in Au/1 % graphene (GP) doped-Ca1.9Pr0.1Co4Ox/n-Si structures at forward biases using impedance spectroscopy analysis

Cited by 25 publications

References 50 publications

A comparative study on dielectric behaviours of Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures with different interlayer thicknesses using impedance spectroscopy methods

A comparative study on dielectric behaviours of Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures with different interlayer thicknesses using impedance spectroscopy methods

Frequency and voltage dependence of dielectric properties, complex electric modulus, and electrical conductivity in Au/7% graphene doped‐PVA/n‐Si (MPS) structures

Physical Design and Dynamical Analysis of Resonant–Antiresonant Ag/MgO/GaSe/Al Optoelectronic Microwave Devices

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