High performance flexible multilevel optical memory based on a vertical organic field effect transistor with ultrashort channel length

Abstract

Organic optical transistor memory (OTM) devices are receiving extensive attention for application in electronics due to low power consumption and high-density storage. However, in conventional organic OTM devices, the photogenerated carriers in the organic semiconductor layer tend to recombine due to the long channel length (usually tens of micrometers), causing a reduced separation efficiency of photogenerated carriers and subsequent small memory windows, which limit their application in optical storage. In this work, a multilevel non-volatile optical memory device based on a vertical thin-film transistor was reported, for which the channel length was successfully downscaled to the nanoscale (tens of nanomenters). It significantly increased the separation efficiency of photogenerated charges, leading to an admirable memory window of 73 V accompanied by enhanced memory ratios, six distinct storage levels along with high responsivity and photosensitivity at low optical power. Moreover, the flexible OTM device exhibited excellent mechanical robustness due to its vertical design, which was much less impacted by the dislocations and in-plane cracks during the mechanical bending process. Furthermore, a logic gate with ‘AND’ and ‘OR’ operations was realized by a single memory device through two optical pulses and an optical memory array was demonstrated to realize the functions of image processing and recognition. This work offers a promising method to fabricate high performance OTM devices, which show great potential in the development of multilevel data storage and image processing.