Engineering the interface of Schottky diodes with a PVA:(CoFe2O4-rGO) nanocomposite for enhanced frequency response via admittance spectroscopy
Küçük Resim Yok
Tarih
2026
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
World Scientific Publ Co Pte Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
This study examines the frequency- and voltage-dependent electrical parameters, interface trap densities (D-it) and relaxation times (tau) in Au/PVA:(CoFe2O4-rGO)/n-Si structures using three complementary admittance methods. CoFe2O4 nanoparticles, synthesized hydrothermally, were incorporated with reduced graphene oxide (rGO) into polyvinyl alcohol (PVA) matrices and spin-coated onto n-Si substrates to form interfacial layers. Capacitance-voltage (C-V) and conductance-voltage (G/ omega -V) measurements spanned - 2.0- + 3.0 V across 0.3 kHz-3 MHz. Pronounced frequency dispersion was observed: forward-bias capacitance at + 3.0 V fell from similar to 9 nF (0.3 kHz) to similar to 2.5 nF (3 MHz), while the normalized conductance peaked near 0.8-1.0 V at all frequencies, with trap saturation above similar to 0.75 V. Hill-Coleman analysis revealed D i t values that decline quasi-exponentially from similar to 1 . 3 & times; 10 (14) eV( - 1) cm (- 2 )at low frequencies to similar to 1 . 0 & times; 10 (13) eV (- 1) cm( - 2 )at high frequencies. Parallel-conductance extraction revealed tau spanning three orders of magnitude, from similar to 120 mu s at 0.20 V to similar to 0.08 mu s at 1.60 V, with the normalized conductance saturating above similar to 0.75 V, consistent with strong field-induced acceleration of trap dynamics and near-complete filling of accessible trap levels under moderate forward bias. This behavior arises because the AC period shortens relative to tau : once the period falls below the trap response time, slower states cease contributing to the measured admittance. The apparent donor concentration decreased from similar to 2 . 1 5 & times; 10(17) cm(- 3) to similar to 7 . 7 & times; 10 (15) cm (- 3) over the same frequency range, while the depletion width expanded from 6.6 mu m to 39.9 mu m, and the peak electric field diminished from similar to 2 . 1 7 & times; 10(5) V/cm to similar to 4 . 7 5 & times; 10(4 )V/cm over the same frequency. Unlike conventional low-dielectric interlayers that cannot fully suppress interface states or reduce series resistance, the high-dielectric PVA:(CoFe2O4-rGO) nanocomposite studied here offers a broader operating window by neutralizing a substantial fraction of N s s while regulating charge transport mechanisms. To our knowledge, this is the first frequency-resolved, multi-method mapping of D-it and tau distributions in such a system, offering practical guidance for engineering nanocomposite interlayers with tailored trap spectra.
Açıklama
Anahtar Kelimeler
[Keyword Not Available]
Kaynak
International Journal of Modern Physics B
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
