Write-Once Read-Many-Times Memory Based on a Single Layer of Pentacene

We realized an organic electrical memory device with a simple structure based on single-layer pentacene film embedded between Al and ITO electrodes. The optimization of the thickness and deposition rate of pentacene resulted in a reliable device with an on/off current ratio as high as nearly 10⁶, which was two orders of magnitude higher than previous results, and the storage time was more than 576 h. The current transition process is attributed to the formation and damage of the interface dipole at different electric fields, in which the current conduction showed a transition from ohmic conductive current to Fowler-Nordheim tunneling current. After the transition from ON- to OFF-state, the device tended to remain in the OFF-state even when the applied voltage was removed, which indicated that the device was very promising for write-once read-many-times memory.