A study on the electrical properties and mechanisms of the non-volatile memory device fabricated utilizing fullerenes embedded in a polymethyl methacrylate layer

Abstract

Three-dimensionally confined nanoparticles embedded in insulating layers have been investigated extensively for their promising applications in nonvolatile memory devices. Among the several types of the nonvolatile memory devices, polymer RAM (PoRAM) based on organic/inorganic nanocomposites have become particularly attractive due to their relatively simple fabrication techniques involved. Even though some studies concerning the bistability phenomenon in organic materials have been reported, very few studies concerning PoRAM consisting of nanoparticles embedded in insulating polymer layer between two electrodes have been performed. This paper presents the electrical bistable properties of PoRAM based on fullerene molecules embedded in a polymethyl methacrylate (PMMA) insulating polymer layer. The hybrid active layers used in this study consist of the PMMA and fullerene molecules composites. Non-volatile memory device with PMMA and fullerene nanocomposite was fabricated by simple method, like as spin-coating. The current-voltage curves show that the conductivity of the devices is relatively low at small applied voltage. The current slightly increases with increasing forward voltage to 2 V and the conductivity of the device maintains low (OFF state). The device current exponentially increases after an applied voltage of above 2 V, and the conductivity of the device becomes relatively high (ON state) and maintains ON state up to an erasing voltage of -3 V. After the erasing voltage is applied to the device, the conductivity of the device becomes low. The ON/OFF ratio was significantly larger than that of the Al/PMMA/Al device due to the existence in the fullerene molecules. The current bistability originated from the charging and discharging in the fullerene molecules by the programming and erasing processes. These results indicate that fullerene based on the PMMA and fullerene hybrid active layer hold promise for potential applications in next-generation nonvolatile memory devices.