High-speed energy-efficient memristor confined in sub-5 nm space with elemental oxygen reservoir layer

Random migration of oxygen vacancies (V_O) leads to unpredictable formation and rupture of conductive filaments (CFs) in oxide-based memristors. In this work, an atomically flat 4.5 nm hafnium oxide (HfO_x) switching layer and a 3.5 nm elemental oxygen reservoir (EOR) layer are confined between two-dimensional HfS₂ and MoS₂ layers, ensuring a homogeneous electric field distribution. The migration and redistribution of V_O within the ultrathin HfO_x switching layer enable the memristive behavior of the device. The EOR-based memristors achieve high set/reset transition speeds of 8 ns and 15 ns, respectively. The electroneutral EOR layer interacts with V_O in the HfO_x switching layer and, together with the HfO_x tunnel layer above the HfS₂, forms a barrier to suppress the high-resistance state current. Reliable endurance up to 10⁵ cycles, and long retention up to 10⁵s are simultaneously obtained. Finally, a high recognition accuracy of 97.0% is achieved, demonstrating potential for low-power neuromorphic computing applications.