Issue

Vol. 18 (2026)

Dipole-Driven Charge Trapping in Monolayer Janus MoSSe for Ultrathin Nonvolatile Memory Devices

https://doi.org/10.1007/s40820-026-02078-y
Eun Bee Ko
School of Materials Science and Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea
Junho Sung
Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
Seon Yeon Choi
School of Materials Science and Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea
Yasir Hassan
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
Jeong‑Ju Bae
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
Jongseok Kim
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
Hyun You Kim
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
Eunho Lee
Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
Min Sup Choi
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
Hyun Ho Kim
School of Materials Science and Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea

Corresponding Author: Hyun Ho Kim

kimhh@gist.ac.kr

Nano-Micro Letters, Vol. 18 (2026), Article Number: 216

Abstract

The continued scaling of flash memory technologies faces challenges such as limited operation speed, poor data retention, and interface defects inherent to conventional three-dimensional architectures. Two-dimensional (2D) materials, with van der Waals interfaces and atomic-scale thickness, offer a promising pathway to overcome these limitations by enabling efficient charge modulation while minimizing surface defects. In this work, a nonvolatile 2D flash memory device is developed employing monolayer Janus MoSSe as the charge-trapping layer and hexagonal boron nitride (h-BN) as an ultrathin tunneling barrier. The intrinsic structural asymmetry of Janus MoSSe induces a strong vertical dipole moment, resulting in enhanced charge trapping, deeper energy barriers, and directional polarization compared with symmetric 2D materials. Consequently, the devices exhibit outstanding retention times exceeding 104 s, endurance beyond 104 program/erase cycles, and large memory window ratios (ΔV/VG,max of 50%–70% for 10 and 6 nm h-BN, respectively), with charge-trapping rates up to 8.96 × 1014 cm−2 s−1. In addition, Janus MoSSe-based devices show synaptic characteristics under electrical pulses and perform recognition simulations in artificial neural networks. These findings establish a design paradigm for 2D memory devices, enabling ultrathin, flexible, and energy-efficient nonvolatile memories.


Highlights:
1 Janus MoSSe-based floating-gate memory exhibits ultrafast charge-trapping dynamics and stable charge retention exceeding 108 s under low-voltage operation.
2 The intrinsic out-of-plane dipole moment in Janus MoSSe effectively suppresses leakage current and enlarges the memory window, even with ultrathin h-BN tunneling layers.
3 The proposed all-van der Waals heterostructure provides a scalable platform for high-speed, energy-efficient, and reliable nonvolatile memory applications.

Keywords

Janus TMDs Nonvolatile memory Floating-gate 2D materials Synaptic device
Ko, Eun Bee, Junho Sung, Seon Yeon Choi, Yasir Hassan, Jeong‑Ju Bae, Jongseok Kim, Hyun You Kim, Eunho Lee, Min Sup Choi, and Hyun Ho Kim. 2026. “Dipole-Driven Charge Trapping in Monolayer Janus MoSSe for Ultrathin Nonvolatile Memory Devices”. Nano-Micro Letters 18 (January):216. https://doi.org/10.1007/s40820-026-02078-y.
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