Refining the Negative Differential Resistance Effect in a TiO_x-Based Memristor

The N-type negative difference resistance (NDR) is characterized by the peak/valley voltage (Vp/Vv) and the corresponding current (Ip/Iv). The N-type NDR is observed in the resistive switching (RS) memory device of Ag|TiO2|F-doped SnO2 at room temperature. After the TiO2 film is equipped with a nanoporous array, the ∼1.2 V gap voltage between Vp and Vv is effectively downscaled to ∼0.5 V, and the gap current of ∼7.23 mA between Ip and Iv is improved to ∼30 mA. It demonstrates that a lower power consumption and faster switching time of the NDR can be obtained in the memristor. Compensations and synergies among the nanoscale conduction filaments (OH-, Ag+, and Vo) are responsible for the refining NDR behavior in our devices. This work provides an efficient method to construct a high-performance N-type NDR effect at room temperature and gives a new horizon on the coexistence of this type of NDR effect and RS memory behaviors.