Resistive switching behaviors mediated by grain boundaries in one longitudinal Al/MoS2&PVP/ITO device

Nonvolatile memory devices based on 2D layered transition metal dichalcogenides have inspired tremendous amounts of research interests in recent years. In this work, resistive switching (RS) devices based on hybrid molybdenum disulphide and Polyvinylpyrrolidone (MoS2&APVP) is explored. One longitudinal Al/MoS2&PVP/ ITO device exhibits three different modes of I-V characteristics, i.e. typical bipolar RS, asymmetrical bipolar RS and threshold switching (TS), which can be explained by the formation and rupture of conducing filaments (CFs) consisting of sulfur vacancy filaments in MoS2 nanoflakes and sulfur ions filaments in PVP. These CFs form from three different kinds of grain boundaries (GBs), intersecting-GB, bisecting-GB, and bridge-GB in which GBs attach one electrode, parallel to the two electrodes, and attach both electrodes, respectively, corresponding to the three modes of I-V characteristics. These three kinds of GBs coexist in one device and the CF forms randomly from one kind of them during sweeping loops. The mechanism was experimentally proved by our results of the increasing probability of typical bipolar RS in device with one layer of PVP thin film inserted into the interface of MoS2&APVP and ITO and other researchers' results in all-surface MoS2 single-layer MoS(2 )devices.