Hybrid organic-inorganic devices offer a simple and low cost route to the fabrication of resistive memory devices. However the switching and conduction mechanisms are not well established. This work compares ZnO-based devices made in the same manner but having two different nanostructure geometries, vertically aligned ZnO nanorods and randomly dispersed ZnO nanoparticles, both embedded within a PMMA host material and sandwiched between two gold electrodes in a crossbar device configuration. Both device types do not require a forming step to initiate switching and exhibit bipolar switching at relatively low operating voltages. In the low field regime both device types exhibit Ohmic behavior, however in the high field regime their switching and conduction mechanisms are distinctly different. ZnO nanorod-based devices exhibit smooth I-V curves and smooth switching behavior and a conduction mechanism that changes from Poole-Frenkel to Schottky emission when switching from the ON state to the OFF state. In contrast, ZnO nanoparticle devices exhibit sharp switching properties with SCLC behavior in the OFF state and Ohmic conduction in the ON state. These differences in the conduction and switching properties of devices containing the same materials clearly demonstrates the importance of the nanostructure geometry and device architecture on the switching and conduction properties of memristor devices. For each device type we discuss the results and propose plausible mechanisms to account for their different behavior.

中文翻译：

---

Nanorods vs Nanoparticles：Au/ZnO-PMMA/Au 非易失性存储器件的比较研究显示纳米结构几何对传导机制和开关特性的重要性

混合有机-无机器件为电阻存储器件的制造提供了一种简单且低成本的途径。然而，开关和传导机制还没有很好地建立。这项工作比较了以相同方式制造但具有两种不同纳米结构几何形状的基于 ZnO 的器件，即垂直排列的 ZnO 纳米棒和随机分散的 ZnO 纳米颗粒，两者均嵌入 PMMA 主体材料中并夹在交叉装置配置中的两个金电极之间。两种器件类型都不需要形成步骤来启动开关并在相对低的工作电压下表现出双极开关。在低场区，两种器件类型都表现出欧姆行为，但在高场区，它们的开关和传导机制明显不同。基于 ZnO 纳米棒的器件表现出平滑的 IV 曲线和平滑的切换行为，以及从导通状态切换到截止状态时从普尔-弗伦克尔发射变为肖特基发射的传导机制。相比之下，ZnO 纳米颗粒器件在关断状态下具有 SCLC 行为，在导通状态下具有欧姆传导，表现出明显的开关特性。包含相同材料的器件的传导和开关特性的这些差异清楚地表明纳米结构几何形状和器件架构对忆阻器器件的开关和传导特性的重要性。对于每种设备类型，我们讨论结果并提出合理的机制来解释它们的不同行为。