Three-terminal organic memory devices

Abstract

An organic electrical bistable device (OBD) has been reported previously, which has an organic∕metal-nanocluster∕organic structure sandwiched between a top and bottom electrode [L. P. Ma, J. Liu, and Y. Yang, Appl. Phys. Lett. 80, 2997 (2002)]. This device can be switched between a low- (OFF) and a high- (ON) conductivity state by external bias. In this article, we report a three-terminal organic memory device, which is realized by wiring out the metal-nanocluster layer of the OBD as the middle electrode. The ON and OFF states of the device can be read out by measuring the potential of the middle electrode. By controlling the interface formation of the device, a three-terminal OBD with a potential change on the middle electrode of more than three orders in magnitude between the OFF state and ON state (from $0.2\mathrm{mV}\text{to}0.77\mathrm{V}$ ) is achieved. By wiring out the middle electrode, the three-terminal OBD can also be considered as two 2-terminal devices stacked together. By proper interface engineering (to be discussed in detail in the text), we found that both the top and bottom devices show electrical bistability and memory effect. This can double the data storage density of the memory device. Details of the device mechanism are provided.