Solution-processable poly(N-vinylcarbazole)-covalently grafted MoS2 nanosheets for nonvolatile rewritable memory devices

Abstract

A novel nonvolatile rewritable memory device based on the soluble poly(N-vinylcarbazole)-chemically modified MoS₂ nanosheets (MoS₂-PVK) was fabricated with the configuration of Au/MoS₂-PVK/ITO. This is the first example of polymer covalently modified MoS₂ nanosheet-based memory devices. As expected, this device exhibited a typical storage performance of nonvolatile rewritable memory, with a turn-on voltage of −1.54 V and an ON/OFF current ratio of 4 × 10². After annealing at 80 °C for 1 h under a nitrogen atmosphere, a high ON/OFF current ratio (up to 3 × 10⁴) and a lower turn-on voltage (−1.31 V), which are among the best reported for MoS₂-based polymer/organic memory devices, were achieved due to enhanced crystallization of PVK, which induced a more efficient intramolecular charge transfer effect between PVK and MoS₂ during the annealing process. The effect of film thickness on the current–voltage characteristics of the MoS₂-PVK-based devices and the memory performance of the MoS₂/PVK blends-based devices have also been explored.