Negative-resistance device using organic thin films

A new negative-resistance device which had a structure of anode/insulating layer/hole transport layer/cathode was fabricated by thermal CVD and vacuum deposition. Its current-voltage characteristics at room temperature showed a remarkable negative resistance. A current peak was observed around 5similar to6V with increasing voltage. It decreased With increasing the width of an insulating layer. The peak voltage also increased with increasing the ionization potential of dye or the barrier of hole tunneling. The current peak decreased with the difference between Fermi level of the anode and ionization potential of insulating layer. These suggest that the negative resistance around 5similar to6V may be explained by the tunneling phenomenon.