Voltage-induced insulator-metal transition at room temperature in an anodic porous alumina thin film

Bistable switching effect, induced by an electric field, in an anodic porous alumina thin film is reported. An electrode was bonded on the surface of a thin film with Ag paste, and I-V characteristic between the electrode and the aluminium substrate was measured The I-V characteristic reveals a reversible resistance change, initiating at +4 V and terminating at –1.5 V at room temperature. Huge electrical resistance change ratio (RR), defined as the ratio of the resistance change to the low resistance state, is observed. The RR is approximately ten million. The resistance in the low resistance state was measured down to 18 K. The temperature dependence of the resistance shows a metal-like behaviour. The huge RR and the temperature dependence of the resistance suggest that an insulator-metal transition is occurred. Excellences of this device are huge RR ratio, easiness of mass production, and containing only common materials. It is a promising material for non-volatile memory with low power consumption and other electrical applications.