Self-rectifying resistance switching memory based on a dynamic p–n junction

Although resistance random access memory (RRAM) is considered as one of the most promising next-generation memories, the sneak-path issue is still challenging for the realization of high-density crossbar memory array. The integration of the rectifying effect with resistance switching has been considered feasible to suppress the sneaking current. Herein, we report a self-rectifying resistance switching (SR-RS) by a newly discovered Li ions migration induced dynamic p–n junction at the Li-doped ZnO and ZnO layer interface. The Au/Li–ZnO/ZnO/Pt structure exhibits a forming-free and stable resistance switching with a high resistance ratio of R _OFF/R _ON ∼ 10⁴ and a large rectification ratio ∼10⁶. In the Li–ZnO/ZnO bilayer, the electric field drives the dissociation and recombination of the self-compensated $L{i}_{Zn}^{-}-L{i}_i^{+}$ complex pairs ($L{i}_{Zn}^{-}:$ p-type substitutional defect; $L{i}_i^{+}:$ n-type interstitial defect) through the transport of $L{i}_i^{+}$ between the two layers, thereby induces the formation of a dynamic p–n junction. Using this structure as a memory stacking device, the maximum crossbar array size has been calculated to be ∼16 Mbit in the worst-case scenario, which confirms the potential of the proposed device structure for the selection-device free and high-density resistance random access memory applications. (paper)