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 crosstalk 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 surmount the crosstalk issue. 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 ROFF/RON ~ 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 Li_Zn^--Li_i^+ complex pairs (Li_Zn^-: p-type substitutional defect; Li_i^+: n-type interstitial defect) through the transport of Li_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.