制备了一种具有多级存储效应的密集ZnO纳米棒阵列阻变存储器件, 借助I-V曲线和荧光光谱分析了器件的电流传导机制和阻变机制, 发现器件在不同的电阻态下分别属于欧姆传导和空间电荷限制电流(SCLC)传导机制。正向电场作用使纳米棒表面耗尽区的氧空位V++密度增大, 完善了电子传输的导电细丝通道, 器件实现了由高阻态向低阻态的转变; 在反向电压作用下, 导电通道断裂, 器件恢复到高阻态。

A multi-level resistive memory device based on the single-layered dense ZnO nanorod arrays was prepared. The mechanisms of current conduction and resistive switching were studied by I-V curve and bias dependence of fluorescence spectra. The dominant conduction mechanisms for the two resistance states are concluded to be Ohmic conduction and space-charge-limited-current (SCLC) conduction, respectively. It is considered that the oxygen vacancies density at the surface depletion region of nanorods is influenced by charge loss in defects of V0 and V+. The increased oxygen vacancies density under forward bias is obtained to build the conductive paths for the electron transportation, resulting in the switching from the high resistance state to the low resistance state. The high resistance state is re-obtained with the paths broken off under reverse voltage.