Tunable dielectric properties and impedance spectroscopy analysis of Au/PVA:(CoFe2O4-rGO)/n-Si structures over a wide frequency and voltage range
Küçük Resim Yok
Tarih
2026
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Springer
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
This study comprehensively examines voltage/frequency-dependent complex dielectric (epsilon*) behaviors, electric-modulus (M*), ac conductivity (sigma(ac)), 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 (epsilon ') below 30, indicative of limited-charge carrier dynamics within extended depletion layers; (ii) the depletion region (- 0.4 V <= V <= + 0.4 V) stabilizes epsilon ' 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 epsilon ' reaching 140 at 0.3 kHz, attributed to interface trap (N-it) charging and orientational polarization of CoFe2O4 nanoparticles. A characteristic dielectric relaxation at 3.0 kHz produces bell-shaped imaginary-dielectric (epsilon '') peaks alongside a significant loss tangent (tan delta) 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 (sigma(ac)) 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 (similar to 17 k Omega) to a compressed resistive response (< 1 k Omega). The voltage-tunable dielectric properties of the interlayer, governed by bias-dependent charge injection and N-it activation, highlight its remarkable potential for next-generation adaptive electronic-devices requiring dynamic dielectric modulation.
Açıklama
Anahtar Kelimeler
[Keyword Not Available]
Kaynak
Journal of Materials Science-Materials in Electronics
WoS Q Değeri
Q2
Scopus Q Değeri
Q2
Cilt
37
Sayı
10
