Abstract: The reversible electrical bistability of a new organic thin film device with a metal/organic/metal sandwich structure is investigated.The anode and cathode metals of the device are Ag and Al,respectively,and were fabricated by vacuum evaporation.The middle medium is 2-(hexahydropyrimidin-2-ylidene)-malononitrile (HPYM).The device,which has polar memory characteristics,can be written from a low-conductance state to a high-conductance state by a voltage pulse and can be erased by a reverse voltage.The device with a thin Al2O3 layer between base metal Al and HPYM can produce different high-conductance states through the application of different positive voltages,resulting in multilevel memory capability.The effect of different electrode combinations on conductance switching devices is studied and UV-Vis absorption spectra and Raman spectra are used to obtain information on the interfaces of the devices.

Key words: organic film device, memory device, electrical bistability, multilevel conductance