We show that irradiation with femtosecond laser pulses can produce robust nanowire heterojunctions in coupled non-wetting metal-oxide Ag-TiO₂ structures. Simulations indicate that joining arises from the effect of strong plasmonic localization in the region of the junction. Strong electric field effects occur in both Ag and TiO₂ resulting in the modification of both surfaces and an increase in wettability of TiO₂, facilitating the interconnection of Ag and TiO₂ nanowires. Irradiation leads to the creation of a thin layer of highly defected TiO₂ in the contact region between the Ag and TiO₂ nanowires. The presence of this layer allows the formation of a heterojunction and offers the possibility of engineering the electronic characteristics of interfacial structures. Rectifying junctions with single and bipolar properties have been generated in Ag-TiO₂ nanowire circuits incorporating asymmetrical and symmetrical interfacial structures, respectively. This fabrication technique should be applicable for the interconnection of other heterogeneous metal-oxide nanowire components and demonstrates that femtosecond laser irradiation enables interfacial engineering for electronic applications of integrated nanowire structures.

Single nanowire memory units are of particular interest in the design of high-density nanoelectronic circuits, but the performance due to weak contact state remains a major problem. In this paper, bonding between core/shell SiC/SiO₂ nanowire and Au electrodes can be improved via local contact engineering with femtosecond (fs) laser irradiation. An optimized heterojunction (Au–SiO₂–SiC) is possible since plasmonic enhanced optical absorption can be localized at the metal–oxide (Au–SiO₂) interface. Electron transport across the barrier and charge accumulation at the oxide–semiconductor (SiO₂–SiC) interface are improved in nanowire circuits. A fast and stable resistance change can be achieved after only one biasing cycle (‘write’) and the written state can be read/extracted at a low voltage (∼ 0.5 V). Unlike other as-built nanowire circuits, the resistance state can be retained for 10 min in the absence of external power, indicating that these devices can be used for short-term memory units. High current tolerance is also provided in the circuit by the surface oxide shell which acts to protect the inner SiC core. The current density carried by the single SiC/SiO₂ nanowire circuit can be as high as ∼3 × 10⁶ A cm⁻² before break down, and that breakdown occurs as a two-stage process.