Electropolymerized PEDOT:PSS-Based Memtransistors for Neuromorphic Computing

Organic electrochemical transistors (OECT) have been reckoned as promising candidates for neuromorphic computing thanks to their low power consumption, small footprint, access to a multitude of memory levels and superior spatio-temporal dynamics. However, the acquisition of non-volatile memory levels has not been straightforward, as some works require the use of auxiliary components such as resistors, preparation of composite channel materials, or surface treatments on substrates to obtain stable and reproducible results. Aiming to simplify the access to these levels in these devices, a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) electropolymerization process is implemented here to controllably deposit conducting fibers in channels of vertical OECTs. By varying the pulse time, not only the number of memory levels is tuned, but also the onset of the first memory level shift. During writing, energy expenditure per switching event is estimated to be on the nJ scale, with clear potential for further reduction. In addition, erasing of memory levels is as well demonstrated by the application of a train of pulses with increasing voltage. The advancements here presented in reproducibility of writing and erasing non-volatile memory levels in OECTs as well as the simple device structure will enable further implementation of neuromorphic hardware in the future.