Electrical bistability of tris-(8-hydroxyquinoline) aluminum (Alq 3)/ZnSe organic-inorganic bistable device

Abstract

We present that the electrical bistability in organic-inorganic bistable devices based on tris-(8-hydroxyquinoline) aluminum (Alq 3) and zinc selenide (ZnSe) with the tri-layer structure of Alq 3/aluminum (Al)/ZnSe. The current–voltage characteristics of the bistable device exhibit two electrical states as low (OFF state) and high (ON state) conductivity with ON/OFF ratio about four orders of magnitude. The conduction mechanisms in both ON and OFF states were analyzed by theoretical model. In the OFF state, the conduction mechanisms can be explained by thermionic emission model, which the ON state can be described by ohmic conduction model. The retention times of both states are more than 8000 s, and the device can reproduce continuous write-read-erase-read switching cycles. Moreover, for the organic-inorganic bistable device was kept at one year in ambient condition without encapsulation. The device still exhibited the electrical bistable behavior. Consequently, the ZnSe layer may be led to improve the lifetime property of the bistable device which acted as a self-encapsulating layer.