Non-volatile WORM memory device based on an acrylate polymer with electron donating carbazole pendant groups

A write-once read-many-times (WORM) memory device based on an acrylate polymer containing electron donating carbazole pendant groups, or poly(2-(9H-carbazol-9-yl)ethyl methacrylate) (PCz), was demonstrated. The as-fabricated device was found to be at its OFF state and could be programmed irreversibly to the ON state. The WORM device exhibited a high ON/OFF current ratio of up to 106, a long retention time in both ON and OFF states, a switching time of 1 ms, and number of read cycles up to ∼107. Compared to that of poly(N-vinylcarbazole) (PVK), the well-defined memory property of PCz can be attributed to the presence of the spacer between the pendant carbazole group and the polymer backbone. The molecular spacer has allowed the transition of the pendant carbazole groups from the disoriented state to the ordered face-to-face conformation at the threshold voltage.