Interfacial engineering and dielectric tunability in Ag/Al/SiO2/n-Si/Ag heterostructures: Novel insights for resistive memory and high-κ electronics

This study presents a comprehensive investigation of the dielectric and electrical properties of Ag/Al/SiO₂/n-Si/Ag heterostructures using impedance spectroscopy, modulus formalism, and temperature-dependent current-voltage (I-V) analysis. The incorporation of an Al interlayer between Ag and SiO₂ introduces unique interfacial effects, modifying charge transport dynamics, dielectric relaxation, and barrier height distribution. Key findings include: Frequency- and voltage-dependent dielectric relaxation, revealing Maxwell-Wagner polarization and interfacial trap effects, with non-Debye behavior due to distributed relaxation times. Temperature-activated conduction mechanisms, including thermionic emission, hopping transport, and space-charge-limited conduction (SCLC), influenced by SiO₂ thickness and defect states.AC conductivity analysis following Jonscher's power law, with distinct low-frequency (ohmic) and high-frequency (dispersive) regimes. Barrier height inhomogeneity, extracted via modified Richardson plots, showing a Gaussian distribution of Schottky barriers due to interfacial disorder. Novelty: Unlike conventional MOS structures, the dual-metal (Ag/Al) electrode enhances interfacial dipoles and modifies charge injection, while the SiO₂/n-Si interface governs dielectric losses and capacitive memory effects. This work bridges the gap between organic-inorganic hybrid dielectrics and traditional SiO₂-based devices, offering insights into defect engineering for tunable dielectric response. Potential Applications.

Non-volatile resistive memory (RRAM) – Exploiting voltage-dependent dielectric relaxation for low-power neuromorphic computing. High-κ gate dielectrics – Optimizing SiO₂ thickness for reduced leakage currents in MOSFETs. Flexible electronics – Hybridizing with polymer composites (e.g., P3HT:PCBM) for stretchable capacitive sensors. Thermal/voltage sensors – Utilizing tanδ and modulus dispersion for environmental sensing applications.