Functional Oxidation of 2D ZrSe 2 Enables High-Performance Threshold Switches

Threshold switching memristors are promising for neuromorphic hardware, yet conductive filament (CF) devices often suffer from poor reliability due to stochastic filament formation and uncontrolled active ion diffusion. This letter reports a vertical Ag/oxidized-ZrSe2/graphene/Au threshold switch in which an amorphous ZrOx matrix containing Ag2Se crystallites is formed from 2D ZrSe2via in situ plasma oxidation and subsequent reaction with the Ag top electrode. The Ag2Se phase serves as a dynamic Ag-ion buffer, stabilizing filament formation and suppressing runaway diffusion. A graphene interlayer further improves the bottom-interface contact and mitigates local field concentration, enhancing switching uniformity. The device achieves a sub-0.204 mV/dec subthreshold swing, 3.7% threshold voltage coefficient of variation, stable operation from 100 pA to 10 μA, and endurance beyond 107switching cycles. These results underscore the functional role of oxidation-derived phases in two-dimensional materials and provide a materials/structure route toward reliable, low-power artificial neuronal devices.