Monolayer optical memory cells based on artificial trap-mediated charge storage and release

TLDR

Monolayer transition metal dichalcogenides offer a direct bandgap and strong light‑matter interactions, making them attractive for flexible, transparent optoelectronics, yet few studies have explored single‑layer optical memory for high‑quality image sensing. We propose a monolayer MoS₂ optoelectronic memory that employs artificially structured charge‑trap layers created by functionalizing the monolayer/dielectric interface, enabling electrically induced charge trapping and optically mediated charge release. The resulting devices exhibit a photo‑responsive memory with a linear dynamic range of ~4,700 (73.4 dB), OFF‑state current below 4 pA, storage lifetimes exceeding 10⁴ s, and eight distinct optical states, marking a substantial advance toward monolayer optoelectronic memory.

Abstract

Monolayer transition metal dichalcogenides are considered to be promising candidates for flexible and transparent optoelectronics applications due to their direct bandgap and strong light-matter interactions. Although several monolayer-based photodetectors have been demonstrated, single-layered optical memory devices suitable for high-quality image sensing have received little attention. Here we report a concept for monolayer MoS2 optoelectronic memory devices using artificially-structured charge trap layers through the functionalization of the monolayer/dielectric interfaces, leading to localized electronic states that serve as a basis for electrically-induced charge trapping and optically-mediated charge release. Our devices exhibit excellent photo-responsive memory characteristics with a large linear dynamic range of ∼4,700 (73.4 dB) coupled with a low OFF-state current (<4 pA), and a long storage lifetime of over 104 s. In addition, the multi-level detection of up to 8 optical states is successfully demonstrated. These results represent a significant step toward the development of future monolayer optoelectronic memory devices.