Memory effect and charge-transport mechanisms of write-once-read-many-times bistable devices based on ZnS quantum dots embedded in poly-4-vinyl-phenol layer

A write-once-read-many-times (WORM) bistable device was prepared, in which ZnS quantum dots doped poly-4-vinyl-phenol (PVP) layer was sandwiched between ITO anode and Al cathode. Current-voltage (I-V) curves showed a switching characteristic with a large ON/OFF ratio of 10 ⁴. The electrical bistability properties and charge-transport mechanisms were discussed in detail based on I-V characteristics. The conduction mechanisms in both ON- and OFF-states were discussed in terms of different theoretical models. The data-retention characteristics of the current-time (I-t) curve exhibited permanent retention ability at ambient conditions.