Tailoring the resistive switching performance of niobium oxide memristors for neuromorphic computing through nitrogen doping

Memristors, which integrate storage and computing in a single device, are promising for neuromorphic computing. In this study, NbO x and nitrogen doped NbO x N y films were prepared by pulsed laser deposition in mixed oxygen nitrogen atmospheres. XPS and EDS confirmd successful and uniform nitrogen incorporation. Pt/NbO x N y /Cu devices exhibited a switching ratio of 3 × 10 5 , which is two orders of magnitude higher than Pt/NbO x /Cu, and stable resistance states exceeding 30,000s in both HRS and LRS. The NbO x N y devices showed only minor performance degradation, with the switching ratio decreasing from 10 5 to 10 4 between 20 and 70 °C and the SET voltage rising from 0.5 to 1 V under 35–90 % RH. Atomic-scale force-field simulations revealed a strong interaction (−1.238 eV) between oxygen vacancies and nitrogen dopants, favoring Vo–N complex formation. These complexes repel adjacent Nb 5+ ions, generating relaxed Nb–Nb regions that facilitate Cu 2+ migration and confine conductive filament growth. As a result, nitrogen doping improves stability and shifts the HRS conduction mechanism from space-charge-limited current to hopping transport, while preserving Ohmic conduction in the LRS. These enhancements expand the dynamic range of synaptic weights, supporting high-precision weight mapping and reliable long-term learning, making NbO x N y memristors strong candidates for energy-efficient neuromorphic computing.