School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Oryong-Dong, Buk-Gu, Gwangju 61005, South Korea.
Phys Chem Chem Phys. 2018 Jun 13;20(23):16176-16183. doi: 10.1039/c8cp02024h.
In ferroelectric (FE) polymer-semiconducting polymer blend based organic resistive random access memory devices (ReRAM), the carriers are injected into the semiconductor region of the blend because of the polarization originated internal electric field in the FE polymer. A higher concentration of semiconducting polymer in the FE polymer-semiconducting polymer blends usually generate a high leakage current and degrades the FE characteristics of the FE polymer resulting in a high OFF current and consequently a low ON/OFF ratio. In order to achieve a high ON/OFF ratio in the FE polymer/semiconducting polymer blends, the FE properties of the FE polymer should be preserved. In this study, organic ReRAMs based on ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and ZnO nanoparticle (NPs) blends exhibiting bipolar resistive switching and a high ON/OFF ratio were realized using a low-cost solution process. Unlike conventional ferroelectric polymer-semiconducting polymer blend systems where FE characteristics are suppressed in ReRAMs, our Au/P(VDF-TrFE)_ZnO NPs/n++Si devices retain the FE characteristics of the P(VDF-TrFE) polymers. Our devices switch between bi-stable resistance states via the ferroelectric-assisted filamentary conduction mechanism. Based on ex situ transmission electron microscopy and elemental mapping analyses, we found that the resistive switching occurs through the formation of conduction paths consisting of Zn-rich/F-deficient regions. The device fabricated at a blend ratio of 20 wt% ZnO NPs in P(VDF-TrFE) matrix exhibited optimal stable resistive switching behavior with an ON/OFF ratio of up to 2 × 107 and a retention time of 104 s.
在铁电（FE）聚合物-半导体聚合物共混物基有机电阻式随机存取存储器（ReRAM）器件中，由于 FE 聚合物中的极化产生的内部电场，载流子被注入共混物的半导体区域。FE 聚合物-半导体聚合物共混物中较高浓度的半导体聚合物通常会产生较高的漏电流，并降低 FE 聚合物的 FE 特性，导致较高的 OFF 电流，从而导致较低的 ON/OFF 比。为了在 FE 聚合物/半导体聚合物共混物中实现高 ON/OFF 比，FE 聚合物的 FE 特性应该得到保留。在这项研究中，使用低成本溶液处理方法实现了基于铁电聚（偏二氟乙烯-三氟乙烯）（P（VDF-TrFE））和氧化锌纳米粒子（NPs）共混物的有机 ReRAM，该共混物表现出双极电阻开关和高 ON/OFF 比。与传统的 FE 聚合物-半导体聚合物共混物系统不同，在 ReRAM 中抑制 FE 特性，我们的 Au/P（VDF-TrFE）_ZnO NPs/n++Si 器件保留了 P（VDF-TrFE）聚合物的 FE 特性。我们的器件通过铁电辅助丝状传导机制在双稳态电阻状态之间切换。基于原位透射电子显微镜和元素映射分析，我们发现电阻开关是通过形成由富 Zn/贫 F 区域组成的传导路径来实现的。在 P（VDF-TrFE）基体中掺杂 20wt% ZnO NPs 的共混物比的器件表现出最佳的稳定电阻开关行为，具有高达 2×107 的 ON/OFF 比和 104 s 的保持时间。
