What question did this study set out to answer?

The aim is to investigate the dielectric behavior and AC conduction of multi-doped oxide/Si interfaces across a range of temperatures and biases.

February 27, 2026Open Access

A comprehensive temperature-dependent impedance spectroscopy of dielectric behavior and AC conduction in Engineered Multi-Doped Oxide/Si Interfaces

Key Points

The aim is to investigate the dielectric behavior and AC conduction of multi-doped oxide/Si interfaces across a range of temperatures and biases.
Impedance spectroscopy conducted at 1 MHz in the temperature range of 110–350 K
Extraction of real and imaginary parts of the dielectric constant
Analysis of electric modulus to study relaxation dynamics and electrode polarization effects
Examination of AC conductivity with respect to temperature and bias intervals
Dielectric constant increases with temperature and forward bias due to enhanced interfacial polarization and charge effects
Real part of electric modulus decreases with rising temperature; imaginary part shows temperature-dependent peaks
AC conductivity follows Arrhenius behavior, with two distinct activation energies identified at low and high temperatures

Abstract

This study presents a comprehensive investigation of the dielectric-behavior, electric modulus response, AC conductivity, impedance, and phase angle of Al/(Zn: Cd: Ni: TiO₂)/p-Si MIS structures over the temperature range of 110–350 K and a bias interval of ±3 V, using impedance spectroscopy at 1 MHz. The real (ε′) and imaginary (ε″) parts of the dielectric constant were extracted from detailed capacitance and conductance measurements, demonstrating a clear dependence on both temperature and applied voltage. The increase in ε′ and ε″ with rising temperature and forward bias is attributed to enhanced interfacial-polarization, dipolar reorientation, space-charge effects, and thermally activated carriers. The electric modulus formalism, employed to analyze relaxation dynamics and suppress electrode polarization, revealed that the real part (M′) decreases with increasing temperature in both depletion and accumulation regions, while the imaginary part (M″) exhibits temperature-dependent peaks, indicative of dielectric relaxation and redistribution of interface states. The results suggest that short-range charge-transport and localized polarization dominate the dielectric response in different regimes of the applied field. Furthermore, the AC conductivity (σAC) increases with temperature, exhibiting an Arrhenius-type behavior. Two activation energies, approximately 5.6 meV at low temperatures and 18.9 meV at higher temperatures, were identified, implying the coexistence of distinct conduction mechanisms: shallow trap-assisted hopping at low temperatures and thermally activated carrier mobility at higher temperatures. These findings provide insights into the charge transport and polarization mechanisms governing the dielectric properties of Zn: Cd: Ni-doped TiO₂-based MIS structures.

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