Oxygen-Vacancy-Engineered Y2O3/CeO2 Nanobrush Superlattices via Laser Heteroepitaxy: Toward High-Performance Memristors.

Abstract

While oxide-based memristors enable CMOS-compatible in-memory computing, their confinement to single-material memristive layers restricts heterogeneous interfacial engineering-limiting neuromorphic adaptability. Here, a unique nanobrush-based Y₂O₃/CeO₂ superlattice structure with an average height of 75 nm is fabricated using diffusion-limited laser epitaxy. Atomic-resolution structural characterization reveals that each Y₂O₃/CeO₂ superlattice nanobrush exhibits self-organized heterogeneous interfaces along (111) crystallographic orientation. Notably, the nanobrush memristor exhibits unipolar switching with a R_ON/R_OFF ratio ∼12 higher than film-based superlattice devices, plus excellent endurance (1000 cycles) and retention (10⁴ s). The enhanced resistive switching in nanobrush memristors likely stems from their brush geometry and space charge enrichment at chevron-like heterointerfaces. XPS analysis confirms abundant oxygen vacancies in the nanobrush-based superlattices, generating substantial mobile ionic defects. The vertically-aligned nanobrush geometry provides abundant conduction pathways for oxygen vacancy migration. Ultimately, these fluorite-bixbyite superlattice nanobrushes demonstrate structurally engineered, energy-efficient, noise-resistant memory for high-density neuromorphic circuits.