Polymer electrical bistable device and memory cells

摘要

Electrical bistable states with the conductivity different by more than four orders in magnitude were observed in a polymer film sandwiched between two metal electrodes. This polymer film was composed of gold nanoparticles, 8-hydroxyquinoline and polystyrene, and was formed by a solution process. The film can be programmed between the two electrical states by an electric field. The as-prepared device, which was in a low conductivity state, exhibited an abrupt increase of current when the device was scanned up to 2.8 volt (V). The high conductivity state can be returned to the low conductivity state at a voltage of -1.8 V in the reverse direction. The device has a good stability in both the states. The transitions are nonvolatile, and the transition from the low to the high conductivity state takes place in nanoseconds, so that the device can be used as a low-cost, high-density, high-speed, and nonvolatile memory. The switching mechanism was studied by investigating the current-voltage characteristics, the temperature dependence of the current, the surface potential atomic force microscopy and the energy levels of the materials. The electronic transition is attributed to the electric-field induced charge transfer between the gold nanoparticles and 8-hydroxyquinoline molecules.