Nonvolatile field-effect transistor (FET) memories containing transition metal dichalcogenide (TMD) nanosheets have been recently developed with great interest by utilizing some of the intriguing photoelectronic properties of TMDs. The TMD nanosheets are, however, employed as semiconducting channels in most of the memories, and only a few works address their function as floating gates. Here, a floating-gate organic-FET memory with an all-in-one floating-gate/tunneling layer of the solution-processed TMD nanosheets is demonstrated. Molybdenum disulfide (MoS2) is efficiently liquid-exfoliated by amine-terminated polystyrene with a controlled amount of MoS2 nanosheets in an all-in-one floating-gate/tunneling layer, allowing for systematic investigation of concentration-dependent charge-trapping and detrapping properties of MoS2 nanosheets. At an optimized condition, the nonvolatile memory exhibits memory performances with an ON/OFF ratio greater than 104, a program/erase endurance cycle over 400 times, and data retention longer than 7 × 103 s. All-in-one floating-gate/tunneling layers containing molybdenum diselenide and tungsten disulfide are also developed. Furthermore, a mechanically-flexible TMD memory on a plastic substrate shows a performance comparable with that on a hard substrate, and the memory properties are rarely altered after outer-bending events over 500 times at the bending radius of 4.0 mm.
Bibliographical noteFunding Information:
R.H.K. and J.L. contributed equally to this work. This research was supported by the third Stage of the Brain Korea 21 Plus Project in 2014, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (Nos. 2014R1A2A1A01005046 and 2014R1A2A1A09005656), and the NRF-2016M3A7B4910530. This material is based upon work supported by the Air Force Office of Scientific Research under award number FA2386-16-1-4058.
All Science Journal Classification (ASJC) codes
- Materials Science(all)