Investigation of Multilevel Resistive Switching in γ-APTES Film with Embedded ZnO Nanoparticles

• Main Authors: Hung Yu-Liang, 洪友良
• Other Authors: You-Lin Wu
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/4vvupk

碩士 === 國立暨南國際大學 === 電機工程學系 === 105 === The main theme of this thesis is to study the resistive switching characteristics of organic insulator material 3-aminopropyltriethoxysilane (γ-APTES) embedded without or with zinc oxide nanoparticles (ZnO NPs). With fixed mixed ratio of ZnO nanoparticles, we also investigated the effect of various concentrations as well as different thicknesses (by different numbers of spin coating) of -APTES on the resistive switching properties of the memory devices. In this work, we prepared solutions with different -APTES concentrations for spin coating. For comparison, we also prepared a solution with a fixed -APTES/ZnO NPs ratio (= 0.1%). After RCA cleaning process, the solutions prepared were then spin-coated onto fluorinated tin oxide (FTO) substrates, followed by a 120℃, 5 min baking on hotplate. Finally, an Al top electrode was evaporated on the sample via metal mask. The completed devices have structures of Al/-APTES/FTO and Al/-APTES+ZnO NPs/FTO, respectively. For devices characterization, semiconductor parameter analyzer Agilent 4156B was used to measure the I-V characteristics under SWEEP mode and retention property under SAMPLING mode. From the I-V characteristics, we can determine the resistive switching of the devices. For each measurement, the top Al electrode was biased positively and bottom FTO electrode negatively. Our experimental results show that, for the same -APTES thickness, better multi-level resistive switching characteristics were found in device with 1% -APTES than the one with 0.1%. It is believed that more conducting paths would be formed in the layer with higher -APTES concentration for more oxygen vacancies existed. It is also noticed that, for fixed -APTES concentration, the device prepared by one-time spin coating can have the better resistive switching characteristics than the one prepared by three-time spin coating. We infer that lower electric field induced in thicker -APTES film defers the electron conduction in conducting paths formed by oxygen vacancies. Finally, we compared the resistive switching characteristics of devices prepared with fixed -APTES concentration but mixed with and without ZnO NPs. it is found that the number of multi-level switching reduces after the device is being added with ZnO NPs. As for retention property, it is found that the devices with fixed -APTES concentration mixed either with or without ZnO NPs has similar current stability under high-resistance and low-resistance states. It is worthy of mention that adding ZnO NPs increases the current level for both high-resistance state and low-resistance state of the devices, indicating that the resistance of the insulator layer is reduced.