Journal Article

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

Kim, Jongseok, Lee, Eunho, Kim, Hyun You, Sung, Junho, Bae, Jeong-Ju, Ko, Eun Bee, Choi, Seon Yeon, Hassan, Yasir, Kim, Hyun Ho, Choi, Min Sup

2026

Overview

Highlights Janus MoSSe-based floating-gate memory exhibits ultrafast charge-trapping dynamics and stable charge retention exceeding 10 8  s under low-voltage operation. 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. The proposed all-van der Waals heterostructure provides a scalable platform for high-speed, energy-efficient, and reliable nonvolatile memory applications. 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 10 4  s, endurance beyond 10 4 program/erase cycles, and large memory window ratios (Δ V / V G,max of 50%–70% for 10 and 6 nm h-BN, respectively), with charge-trapping rates up to 8.96 × 10 14  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.

• Publisher: Springer Nature Singapore,Springer Nature B.V,Springer,SpringerOpen
• Subject: 2D materials / Artificial neural networks / Boron nitride / Dipole moments / Electric fields / Electrons / Energy / Engineering / Flash memory (computers) / Floating-gate / Graphene / Heterostructures / Janus TMDs / Leakage current / Linux / Memory devices / Monolayers / Nanoscale Science and Technology / Nanotechnology / Nanotechnology and Microengineering / Nonvolatile memory / Retention / Simulation / Surface defects / Synaptic device / Thickness / Trapping / Two dimensional materials