Core-shell quantum dot-enabled monolayer MoS2 memories with high endurance

Abstract

Nonvolatile memories based on low-dimensional materials are pivotal for miniaturized data storage but face challenges in endurance and charge retention. We report a mixed-dimensional memory architecture integrating monolayer MoS₂ with CdSe@CdS core-shell quantum dots (QDs) to address these limitations. By synthesizing polyhedral QDs with facet-engineered surfaces and electrochemically inert passivating ligands, interfacial defects are substantially minimized, enabling efficient charge confinement within CdSe cores via Fowler-Nordheim tunneling. The optimized heterostructure device demonstrates a memory window of 140 V, an on/off ratio of 10⁶, endurance exceeding 5 × 10⁴ cycles, and 96.5% charge retention over 10 years—outperforming previously reported QD-based memories. Furthermore, the cascaded charge transfer mechanism (MoS₂→CdS→CdSe), corroborated by electrical measurements, highlights the critical role of synergistic structural and surface optimization in suppressing charge leakage. This work establishes a scalable platform combining 2D semiconductors and defect-engineered QDs, offering insights into charge dynamics and advancing the development of high-performance, nanoscale nonvolatile memories.