Interfacial dipole in organic p–n junction to realize write-once–read-many-times memory

A new approach is exploited to realize nonvolatile organic write-once–read-many-times (WORM) memory based on copper phthalocyanine (CuPc)/hexadecafluoro-copper-phthalocyanine (F16CuPc) p–n junction. The as-fabricated device is found to be at its ON state and can be programmed irreversibly to the OFF state by applying a negative bias. The WORM device exhibits a high ON/OFF current ratio of up to 2.6 × 104. An interfacial dipole layer is testified to be formed and destructed at the p–n junction interface for the ON and OFF states, respectively. The ON state at positive voltage region is attributed to the efficient hole and electron injection from the respective electrodes and then recombination at the CuPc/F16CuPc interface, and the transition of the device to the OFF state results from the destruction of the interfacial dipole layer and formation of an insulating layer which restricts charge carrier recombination at the interface.

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► Organic WORM memory device based on CuPc/F16CuPc p–n junction.
► The as fabricated device exhibits an ON state and it can be turned to OFF state by a reverse bias.
► The ON/OFF current ratio reaches up to 2.6 × 104.
► Interfacial dipole is formed in the CuPc/F16CuPc p–n junction.
► The ON/OFF transition is controlled by the interfacial dipole formation and destruction.