Artificial synaptic and self-rectifying properties of crystalline (Na1-xKx )NbO3 thin films grown on Sr2Nb3O10 nanosheet seed layers

Abstract

Crystalline (Na1-xKx)NbO3 (NKN) thin films were deposited on Sr2Nb3O10 /TiN/Si (S-TS) substrates at 370 degrees C. Sr2Nb3O10 (SNO) nanosheets served as a template for the formation of crystalline NKN films at low temperatures. When the NKN film was deposited on one SNO monolayer, the NKN memristor exhibited normal bipolar switching characteristics, which could be attributed to the formation and destruction of oxygen vacancy filaments. Moreover, the NKN memristor with one SNO monolayer exhibited artificial synaptic properties. However, the NKN memristor deposited on two SNO monolayers exhibited self-rectifying bipolar switching properties, with the two SNO monolayers acting as tunneling barriers in the memristor. The conduction mechanism of the NKN memristor with two SNO monolayers in the high-resistance state is attributed to Schottky emission, direct tunneling, and Fowler-Nordheim (FN) tunneling. The current conduction in this memristor in the low-resistance state was governed by direct tunneling and FN tunneling. Additionally, the NKN memristor with two SNO monolayers exhibited large ON/OFF and rectification ratios and artificial synaptic properties. Therefore, an NKN memristor with two SNO monolayers can be used for fabricating artificial synaptic devices with a cross-point array structure. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.