Heterostructured Vertical Organic Transistor for High-Performance Optoelectronic Memory and Artificial Synapse

Organic field-effect transistor (OFET) memory has received widespread attention due to its easy integration, precise charge modulation, and multi-level memory. However, the performance of organic memory still needs to be improved for its practical application, and the reported technologies are strongly dependent on an additional charge-trapping layer, which increases the complexity of the device. Here, we report a heterostructured vertical organic memory transistor, which uses a p/n semiconductor bulk heterojunction as a semiconductor layer without using any additional charge-trapping layers. The device exhibits a large memory window of 52 V, and the memory ratio reaches 105 through electrical operation. Benefiting from the formation of the p/n semiconductor interface and the nanometer-scale transmission length, under the stimulation of visible light, the device achieved a 58 V memory window, high memory ratio 105, and retention characteristics of over 10 years, which is better than those of most reported optical organic memory devices. More interestingly, we found that as the level of the doping in the n-type semiconductor increased, the device could transform from nonvolatile memory to artificial synapse, which is associated with the morphology of a heterojunction structure. Hence, we demonstrate a novel technique to manufacture high-performance nonvolatile optoelectronic memory and artificial synapse, which shows great potential in OFET-based memory and neuromorphic devices.