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Frequency and Voltage-Dependent Dielectric Properties and AC Electrical Conductivity of (Au/Ti)/Al₂O₃/n-GaAs with Thin Al₂O₃ Interfacial Layer at Room Temperature

100%

Güçlü Ç., Özdemır A., Kökce A., Altindal Ş.

Acta Physica Polonica A

2016

vol. 130

issue 1

325-330

An (Au/Ti)/Al₂O₃/n-GaAs structure with thin (30 Å) interfacial oxide layer (Al₂O₃), formed by atomic layer deposition technique is fabricated to investigate both frequency and applied bias voltage dependences of real and imaginary parts of dielectric constant (ε' and ε'') and electric modulus (M' and M''), loss tangent tanδ and ac electrical conductivity σ_{AC} in a wide frequency range from 1000 Hz to 1 MHz at room temperature. The dielectric properties of the (Au/Ti)/Al₂O₃/n-GaAs metal-insulator-semiconductor structure are obtained using the forward and reverse bias capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements in the applied bias voltage range from -4 V to +4 V, at room temperature. Experimental results show that the dielectric parameters were strongly frequency and voltage dependent. For each frequency the (C-V) plots show a peak and the change in frequency has effect on both the intensity and position of the peak. ε', ε'' and tanδ decrease with increasing frequency, whereas σ_{AC} increases with increasing frequency at applied bias voltage. M' increases with the increasing frequency and reaches a maximum. M'' shows a peak and peak position shifts to higher frequency with increasing applied voltage. It can be concluded that the ε', ε'', tanδ, M', M'' and σ_{AC} values of the (Au/Ti)/Al₂O₃/ n-GaAs structure are strongly dependent on both the frequency and applied bias voltage especially in the depletion and accumulation region. Also, the results can be deduced to imply that the interfacial polarization is easier at low frequencies, therefore contributing to the deviation of dielectric properties and AC electrical conductivity of (Au/Ti)/Al₂O₃/n-GaAs structure.

The Role of Hydrostatic Pressure in Electrical Properties of Au/n-GaAs Schottky diodes with Substituted Polyaniline Interfacial Layer

100%

Özdemir A., Abdolahpour Salari M., Kökce A., Uçar N.

Acta Physica Polonica A

2017

vol. 132

issue 3

1118-1121

Au/polymer P2ClAn(H₃BO₃)/n-GaAs Schottky barrier diodes, where P2ClAn stands for poly(2-chloroaniline), have been fabricated. To fabricate Schottky diodes with polymer interface, n-type GaAs wafer was used. The P2ClAn polymer solution was applied on the front face of the n-GaAs wafer by a pipette. The P2ClAn emeraldine salt was chemically synthesized by using boric acid (H₃BO₃). Schottky diode parameters, such as ideality factor, barrier height and series resistance have been measured, as functions of hydrostatic pressure, using the current-voltage technique. The ideality factor values of Au/P2ClAn/n-GaAs Schottky barrier diodes have decreased from 3.38 to 3.01, the barrier height has increased from 0.653 to 0.731 eV at 0.36 kbar and series resistances were ranging from 14.95 to 14.69. The results obtained from I-V characteristics of Au/P2ClAn/n-GaAs Schottky barrier diodes show that pressure treatment improves the rectifying properties of the diodes. These diodes can be used as pressure-sensitive capacitors, due to pressure-dependence of diode parameters.

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2 Acta Physica Polonica A

1 2017

1 2016

2 Kökce A.

1 Abdolahpour Salari M.

1 Altindal Ş.

1 Güçlü Ç.

1 Uçar N.

1 Özdemir A.

1 Özdemır A.

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Frequency and Voltage-Dependent Dielectric Properties and AC Electrical Conductivity of (Au/Ti)/Al₂O₃/n-GaAs with Thin Al₂O₃ Interfacial Layer at Room Temperature

The Role of Hydrostatic Pressure in Electrical Properties of Au/n-GaAs Schottky diodes with Substituted Polyaniline Interfacial Layer