Akademik Veri Yönetim Sistemi
Journal of Materials Science: Materials in Electronics, cilt.37, sa.10, 2026 (SCI-Expanded, Scopus)
This study comprehensively examines voltage/frequency-dependent complex dielectric (ε*) behaviors, electric-modulus (M*), ac conductivity (σac), Nyquist-diagram in the Au/PVA:(CoFe2O4–rGO)/n–Si structures by using impedance spectroscopy (IS) measurements in the wide-range (0.3 kHz–3 MHz) and voltage (− 2.0 V/ + 3.0 V). Through a comprehensive dielectric-voltage-frequency analysis, three distinct operational regions are identified: (i) the reverse bias region (− 2.0 V ≤ V ≤ − 0.4 V) shows notably low and frequency-independent real dielectric (ε′) below 30, indicative of limited-charge carrier dynamics within extended depletion layers; (ii) the depletion region (− 0.4 V ≤ V ≤ + 0.4 V) stabilizes ε′ between 10 and 15, providing a consistent baseline for semiconductor parameter extraction; and (iii) the forward bias region (0.0 V ≤ V ≤ 3.0 V) reveals an extraordinary dielectric enhancement, with ε′ reaching 140 at 0.3 kHz, attributed to interface trap (Nit) charging and orientational polarization of CoFe2O4 nanoparticles. A characteristic dielectric relaxation at 3.0 kHz produces bell-shaped imaginary-dielectric (ε″) peaks alongside a significant loss tangent (tanδ) of 140 at 0 V. Analysis of the real/imaginary electrical modulus (M′, M″) indicates distributed relaxation processes dominated by Maxwell–Wagner (MW) interfacial polarization, with peak M″ values between 0.28 and 0.30 under strong forward bias. AC conductivity (σac) exhibits a substantial exponential increase, attaining 0.09 S/m at 3 MHz representing nearly a two-order magnitude rise. Impedance-spectra reveal a systematic transition from capacitance-dominated behavior (~ 17 kΩ) to a compressed resistive response (< 1 kΩ). The voltage-tunable dielectric properties of the interlayer, governed by bias-dependent charge injection and Nit activation, highlight its remarkable potential for next-generation adaptive electronic-devices requiring dynamic dielectric modulation.