Plasmonic‐Radiation‐Enhanced Metal Oxide Nanowire Heterojunctions for Controllable Multilevel Memory

Nanowire memristor devices that display multilevel memory effects are of great interest for high‐density storage, however, numerous challenges remain in fabricating high‐quality, stable memory units. A plasmonic‐radiation‐enhanced technique is introduced in this work for scalably forming nanowire multilevel memory units with superior properties. Femtosecond laser irradiation of gold‐titanium dioxide nanowire‐gold structures results in plasmonic‐enhanced optical absorption in the TiO 2 locally at the metal‐oxide interface. This produces junctions with superior mechanical and electrical contact, and engineers a concentration of charged defects in the TiO 2 near the interface, which enables stable multilevel memory behavior without the need for a traditional electroforming step. The memory units produced display eight‐level current amplification under continuous forward voltage cycles, and can replicate complex multilevel memory sequences without interference between the different multilevel states.