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

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 RON/ROFF 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.