Interfacial gating of nano-ampere resistive switching in Si/SiOx/ZnO heterostructures for energy-efficient electronics.

A highly tunable and electrically robust resistive-switching platform based on Si/SiOx/ZnO heterostructures is demonstrated, where transverse electric-field gating enables deterministic, precise control of lateral charge transport. Electrical characterization reveals that the lateral device voltage exhibits a pronounced differential conductance maximum and gate-field-induced modulation of the density of states near the Fermi level. Current-voltage transport measurements indicate a crossover between Ohmic and trap-charge-limited conduction (TCLC) regimes, governed by trap-mediated carrier dynamics and electric-field-driven charge redistribution. Using a four-terminal device architecture, reversible gate-bias modulation enables reproducible switching between the high-resistance state (HRS) and low-resistance state (LRS), while allowing simultaneous read and write operations. The switching behavior is attributed to modulation of carrier density of the ZnO conducting channel. The resistance state is uniquely determined by the polarity of the applied gate bias, providing deterministic binary-like memory functionality. Furthermore, controlled gate-voltage variation enables programmable multilevel resistance states, highlighting the potential of these heterostructures for analog and neuromorphic computing applications. Under a constant lateral bias current of 300-500 nA, the devices exhibit stable ultra-low-power operation, maintaining reproducible resistive switching cycles over more than 4000 s without measurable degradation. Device performance is strongly dependent on the ZnO layer thickness. Among the investigated structures, a ZnO thickness of 72 nm delivers the best switching performance, achieving a resistance ratio of approximately 25 under the present measurement conditions. To understand the microscopic origin of the observed behavior, first-principles density functional theory (DFT) calculations were performed. The calculations identify interfacial silicon and oxygen ions as key mediators of field-driven charge redistribution and localized state formation, which directly influence carrier transport and resistive switching characteristics. The theoretical results provide strong support for the experimentally observed modulation of density of states and conduction pathways. By establishing electric-field gating as an effective control parameter alongside structural engineering, this work advances Si/SiOx/ZnO heterostructures as a scalable and energy-efficient platform for high-density memory technologies and next-generation neuromorphic computing architectures.