Exploring the dielectric and AC transport characteristics of Au/(Sn:Fe₂O₃)/n-Si diodes using impedance spectroscopy over extended frequency and voltage intervals

This work focuses on the evaluation of essential dielectric characteristics of the (Sn:Fe2O3) interlayer, including the real and imaginary components of the complex dielectric constant (epsilon* = epsilon ' - j epsilon ''), electric modulus (M* = M ' + jM ''), and complex impedance (Z* = Z ' - jZ ''). To enhance the accuracy of the analysis related to dielectric response and charge transport mechanisms, capacitance and conductance were measured under varying frequencies (0.5 kHz to 2 MHz) and applied bias (+/- 3 V). The epsilon '' and tan delta versus ln(f) profiles reveal distinct peak formations within the voltage window of 0.7 V to 3 V, with their shifting positions attributed to voltage-induced rearrangements of trapped charges and polarization effects. Dielectric loss (tan delta), AC conductivity (sigma ac), and phase angle (theta) were also derived from the experimental data. The analysis confirms a strong dependence of these parameters on both frequency and voltage, particularly at low and intermediate frequencies where interface states, Maxwell-Wagner polarization, and series resistance significantly affect the response. Remarkably, the (Sn:Fe2O3) interlayer exhibits a high dielectric constant (epsilon ' approximate to 337.8 at 0.5 kHz), surpassing that of SiO2 by nearly 89 times, highlighting its potential as a high-k dielectric with enhanced energy storage capability in metal-semiconductor structures. The impedance spectra (Nyquist plots) show single semicircles, typical of Debye-type relaxation. Additionally, the ln(sigma ac) vs. ln(f) graph exhibits three distinct linear regions, each corresponding to different dominant conduction processes active at low, mid, and high frequencies.

Journal

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS

Year

2025

Volume

36

Issue

28

ISSN

0957-4522

eISSN

1573-482X

DOI

10.1007/s10854-025-15906-5

WoS UID

WOS:001587935800005

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