title: Flexible Nonvolatile Transistor Memory with Solution-Processed Transition Metal Dichalcogenides.
abstract: 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 MoS2nanosheets in an all-in-one floating-gate/tunneling layer, allowing for systematic investigation of concentration-dependent charge-trapping and detrapping properties of MoS2nanosheets. 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 × 103s. 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.
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
authors.forename: Richard Hahnkee
authors.initials: RH
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
authors.forename: Jinseong
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
authors.forename: Kang Lib
authors.initials: KL
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
authors.forename: Suk Man
authors.initials: SM
authors.lastname: Cho
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Republic of Korea.
authors.forename: Dong Ha
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
authors.forename: Cheolmin
authors.initials: C
authors.lastname: Park
keywords: flexible memories; floating-gate/tunneling layers; liquid exfoliation; nonvolatile memories; transition metal dichalcogenides