Electrical relaxation in Al2O3-based MIS Schottky structures: insights into interfacial polarization and hopping transport
Applied Physics A: Materials Science and Processing, cilt.132, sa.9, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 132 Sayı: 9
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s00339-026-10069-4
- Dergi Adı: Applied Physics A: Materials Science and Processing
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Ac conductivity, Al2O3, Dielectric relaxation, Electric modulus, Impedance spectroscopy, MIS structure
- Gazi Üniversitesi Adresli: Evet
Özet
The electrical and dielectric properties of Au/Al2O3/n-Si/Al MIS-type Schottky structures fabricated using sol–gel derived Al2O3 interfacial layer were systematically investigated through dielectric, electric modulus, conductivity, and impedance spectroscopy analyses. The Al2O3 thin film was deposited onto n-Si substrates by spin coating and subsequently annealed at 1100 °C to improve crystallization. XRD analysis revealed the coexistence of α- and β-Al2O3 phases, indicating the formation of a multiphase structure, while SEM observations demonstrated non-uniform surface morphology accompanied by microcracks, voids, and grain-like features caused by high-temperature-induced structural reorganization. The dielectric behavior was clearly dependent on applied voltage and frequency. Interfacial polarization, space-charge accumulation, and interface-state effects were primarily responsible for the rise in dielectric permittivity and dielectric loss at low frequencies. The absence of distinct loss peaks suggested a non-Debye relaxation process resulting from interfacial heterogeneity. Additional interface-related relaxation processes were identified by modulus analysis, where the frequency-dependent shift of the peaks indicated trap-assisted relaxation associated with localized charge carriers. Furthermore, Nyquist modulus graphs supported the existence of widespread relaxation behavior by showing depressed arcs rather than perfect semicircles. The frequency-dependent ac conductivity was successfully analyzed using Jonscher’s universal power law, and the nonlinear fitting results demonstrated excellent agreement wıth the experımental data over the entire investigated frequency range. overall, the electrical response of the Au/Al2O3/n-Si/Al MIS structure is predominantly governed by interface-state distribution, interfacial polarization, trap-assisted carrier dynamics, and dispersive charge transport, highlighting the critical role of multiphase Al2O3 interfacial layers in tuning dielectric relaxation and charge transport mechanisms in MIS-based electronic devices.