Lim Zhe Xi, Cheong Kuan Yew
Electronic Materials Research Group, School of Materials & Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia.
Phys Chem Chem Phys. 2015 Oct 28;17(40):26833-53. doi: 10.1039/c5cp04622j.
Extracted, formulated, and processed natural Aloe vera has been used as an active layer for memory applications. The functional memory device is realized by a bottom-up structure of ITO/Aloe vera/Al in which the Aloe vera is spin-coated after mixing with different concentrations of ethanol (0-80 wt%) and subsequently dried at different temperatures (50-120 °C). From the current density-voltage measurements, the device can exhibit a reproducible bipolar switching characteristic with pure Aloe vera dried at 50 °C. It is proposed that charges are transported across the Aloe vera layer via space-charge-limited conduction (SCLC), and clusters of interstitial space formed by the functional groups of acemannans and de-esterified pectins in the dried Aloe vera contribute to the memory effect. The formation of charge traps in the Aloe vera layer is dependent on the drying temperature. The drying temperature of a memory-switching Aloe vera layer can be extended to 120 °C with the addition of appropriate amounts of ethanol. The concept of using natural Aloe vera as an active material for memory applications has been demonstrated, and the read memory window, ON/OFF ratio, and retention time are approximately 5.0 V, 10(3), and >10(4) s, respectively.
提取、配制和加工后的天然芦荟已被用作记忆应用的活性层。功能性记忆器件通过ITO/芦荟/Al的自下而上结构实现，其中芦荟在与不同浓度的乙醇（0-80 wt%）混合后旋涂，并随后在不同温度（50-120°C）下干燥。从电流密度-电压测量结果来看，该器件对于在50°C下干燥的纯芦荟可呈现出可重复的双极开关特性。据推测，电荷通过空间电荷限制传导（SCLC）在芦荟层中传输，并且干燥芦荟中乙酰化甘露聚糖和去酯化果胶的官能团形成的间隙空间簇有助于记忆效应。芦荟层中电荷陷阱的形成取决于干燥温度。通过添加适量的乙醇，记忆开关芦荟层的干燥温度可扩展至120°C。使用天然芦荟作为记忆应用活性材料的概念已得到验证，读取记忆窗口、开/关比和保持时间分别约为5.0 V、10³和>10⁴ s。
