| Summary: | 碩士 === 國立東華大學 === 電機工程學系 === 104 === Keywords：Resistive Random Access Memory, Transparent, Flexible, Graphene Oxide, Oxygenated Levels
Resistive random access memory (RRAM) has many outstanding performances, and been regarded as high-potential emerging nonvolatile memory. However, the resistance switching mechanism of RRAM is still indeterminate, and the conductive filament theory is widely accepted by most researchers. The conductive filament is related to the number of oxygen vacancy in the resistive switching layer. In this study, we use graphene with various oxygenated levels to fabricate RRAM devices.
We used low oxygenated levels graphene (GO16) and high oxygenated levels graphene to fabricate various structures of RRAM. ITO/ZnO/GO16/ITO and ITO/ZnO/GO64/ITO are transparent RRAM devices. Under visble light, the transmittance of the transparent RRAM devices is over 75%, but it is only 50% under purple and blue lights. The distributions of HRS and LRS are very stable and uniform. Cu/GO16/Al and Cu/GO64/Al are flexible RRAM devices. Because a lot of Cu ions diffuse from the top electrode to resistive switching layer, the thick conductive filament is formed, and becomes random disruption. The current of HRS is unstable, but the devices can be still operated after bending test. Al/GO16/Al and Al/GO64/Al are flexible RRAM. The distributions of HRS and LRS are still stable after bending test. The retention time and the endurance of all device can reach 105s and 103 times, respectively.
In conclusion, we can control the thickness of the filament by changing the oxidation of the graphene. Cu top electrode makes the resistive switching layer with excessive Cu ions, casuing the thicker conductive filament, and the conductive filament becomes random disruption. Both make the current of HRS unstable. The thin conductive filament is easier to be disrupted between the top electrode and resistive switching layer, and makes the current of HRS stable and uniform.
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