Programmable polymer thin film and non-volatile memory device


Building on the success of organic electronic devices, such as light-emitting diodes and field-effect transistors, procedures for fabricating non-volatile organic memory devices are now being explored. Here, we demonstrate a novel organic memory device fabricated by solution processing. Programmable electrical bistability was observed in a device made from a polystyrene film containing gold nanoparticles and 8-hydroxyquinoline sandwiched between two metal electrodes. The as-prepared device, which is in a low-conductivity state, displays an abrupt transition to a high-conductivity state under an external bias of 2.8 V. These two states differ in conductivity by about four orders of magnitude. Applying a negative bias of 1.8 V causes the device to return to the low-conductivity state. The electronic transition is attributed to the electric-field-induced charge transfer between the gold nanoparticles and 8-hydroxyquinoline. The transition from the low- to the high-conductivity state takes place in nanoseconds, and is non-volatile, indicating that the device may be used for low-cost, high-density memory storage.

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Figure 1: Current–voltage curve (a) and device structure (b) for a device of structure Al/Au−DT+8HQ+PS/Al.
Figure 2: Write–read–erase cycles of device Al/Au−DT+8HQ+PS/Al.
Figure 3: Arrhenius plot of temperature dependence of current for Al/Au−DT+8HQ+PS/Al in the high-conductivity state.
Figure 4: Current–voltage curve of the device Al/Au−DT+8HQ+PS/Al in the high-conductivity state.
Figure 5: Scanning surface potential AFM image of Au−DT+8HQ+PS film with aluminium as bottom electrode and silicon wafer as substrate.
Figure 6


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We thank D. Sievers for calculating the HOMO–LUMO levels of 8HQ and writing the program for the write–read–erase cycle measurement. This work is financially supported by the Air Force Office of Scientific Research (grant no. FA9550-04-0215, programme manager Y-C Lee).

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Correspondence to Yang Yang.

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