  We have studied the electrical field induced conductance transition in thin
film of Perylenetetracarboxylic dianhydride sandwiched between two metal
electrodes, from an insulating state to conducting state with a high ON-OFF
ratio in those devices, where one of electrodes is either Al or Cu. Temperature
dependence of resistivity shows semiconducting behavior in OFF-state, but it
shows metallic behavior in the ON-state. Devices with a thin intermediate layer
of LiF between metal electrode and organic layer, or devices fabricated in
planar configuration do not show switching behavior. All these suggest that
conducting pathways are responsible for the electric field induced conductance
transition.
