Schottky barrier reduction on optoelectronic responses in heavy ion irradiated WSe2 memtransistors

Two-dimensional transition metal dichalcogenide-based memtransistors provide simulation, sensing, and storage capabilities for applications in a remotely operated aerospace environment. Swift heavy ion (SHI) irradiation technology is a common method to simulate the influences of radiation ions on electronic devices in space environments. Here, SHI irradiation technology under different conditions was utilized to produce complex defects in WSe2-based memtransistors. Low-resistance state to low-resistance state (LRS-LRS) switching behaviors under light illumination were achieved and photocurrent responses with different spike trains were observed in SHI-irradiated memtransistors, which facilitated the design of devices with enriched analog functions. Reduction of the Schottky barrier height due to the introduced defects at the metal/WSe2 interface was confirmed to be the major factor responsible for the observed behaviors. 1T phase and concentric circle-type vacancies were also created in the SHI-irradiated 2H-WSe2 channel besides the amorphous structure; these complex defects could seriously affect the transport properties of the devices. We believe that this work serves as a foundation for aerospace radiation applications of all-in-one devices. It also opens a new application field of heavy ion irradiation technology for the development of multiterminal memtransistor-based optoelectronic artificial synapses for neuromorphic computing.