Multifunctional molybdenum disulfide flash memory using a PEDOT:PSS floating gate

Kyungho Yun,Jung Joon Lee,Seongin Hong,Junwoo Park,Sunkook Kim,Sunjong Lee,Hocheon Yoo

doi:10.1038/s41427-021-00307-x

Abstract

Two-dimensional transition metal dichalcogenide materials (TMDs), such as molybdenum disulfide (MoS2), have been considered promising candidates for future electronic applications owing to their electrical, mechanical, and optical properties. Here, we present a new concept for multifunctional MoS2 flash memory by combining a MoS2 channel with a PEDOT:PSS floating layer. The proposed MoS2 memory devices exhibit a switching ratio as high as 2.3 × 107, a large memory window (54.6 ± 7.80 V), and high endurance (>1,000 cycles). As the PEDOT:PSS film enables a low-temperature solution-coating process and mechanical flexibility, the proposed P-memory can be embedded on a polyimide substrate over a rigid silicon substrate, offering high mechanical endurance (over 1,000 cycle bending test). Furthermore, both MoS2 and PEDOT:PSS have a bandgap that is desirable in optoelectronic memory operation, where charge carriers are stored differently in the floating gate depending on light illumination. As a new application that combines photodiodes and memory functions, we demonstrate multilevel memory programming based on light intensity and color.

Highlights

With the advent of the fourth industrial revolution, consumer electronics are in dire need of versatility beyond conventional electronic functions[1,2,3,4]
The memory device is composed of multilayer MoS2 as the channel; PEDOT:Poly(4-styrene sulfonate) (PSS) of 80 nm thickness as the floating gate; 80 nm- and 40 nmthick Al2O3 as a tunneling dielectric layer (TDL) and a passivation layer (PL), respectively; Ti/Au
We spin-coated a PEDOT:PSS layer on top of a blocking dielectric layer (BDL) SiO2 layer, and thereby, the PEDOT:PSS acted as a charge trapping layer for data storage operation (Fig. 1b, c)

Summary

Introduction

With the advent of the fourth industrial revolution, consumer electronics are in dire need of versatility beyond conventional electronic functions[1,2,3,4]. Current electronics demand the development of multifunctional memory devices with characteristics such as mechanical flexibility[9,10,11], multilevel storage[12,13], neuromorphic functions[14,15], and tunable memory operation[16], along with the conventional expectation of excellent memory features. Existing silicon-based memory processes and structures have limitations in developing new features when the multifunctional memory. TMDs have shown the possibility of new electronic device features such as gate-tunable memristic behavior[16,27], neuromorphic functions[28], and optoelectronic properties[29,30]

Methods

Results

Conclusion