Femtosecond laser induced oxygen vacancies in CeO2 with filament-type resistive switching memory

Memristors made from metal oxides mainly rely on resistive switching (RS) due to the migration of oxygen vacancies for binary states. Oxygen vacancy engineering is therefore of great significance for improving the RS performance of metal oxides. In this work, a non-destructive femtosecond-laser strategy is demonstrated to modify the surface states of CeO2 epitaxial films and induce oxygen vacancies for enhanced RS performance. Morphology and structure remain stable in laser-treated CeO2 films, but surface chemistry shows increased oxygen vacancies and adsorbed oxygens. Electrical measurement shows significant enhancement in RS ratios of memristors made from laser-treated CeO2. An average RS ratio of 65 is achieved in laser-treated CeO2 epitaxial films for 10 times. The laser-treated CeO2 epitaxial films for 10 times exhibits excellent stability. As identified by linearly fitting their I-V curve, resistive switching mechanism transfers from interface-limited Schottky emission to bulk-limited filament formation between untreated CeO2 and laser-treated CeO2 for 10 times. The study advances the understanding of RS mechanism in terms of oxygen vacancies and provides a single-step, large-scale, and energy-effective laser engineering route for non-destructive memristive material manipulation.