Bi<sub>2</sub>O<sub>2</sub>Se-Based Monolithic Floating-Gate Nonvolatile Memory with Enhanced Charge Retention and Switching Performance.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41247341.
- Also identified by DOI 10.1021/acsnano.5c14437 and PMC identifier 12676734.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The continuous scaling of conventional floating-gate memories faces major challenges due to charge leakage and complex multilayer architectures. Here, we report a monolithic nonvolatile memory (NVM) device constructed using a single 2D material, Bi<sub>2</sub>O<sub>2</sub>Se, that integrates channel, charge storage, and tunneling functions within the same material system. Upon UV-ozone treatment, semiconducting Bi<sub>2</sub>O<sub>2</sub>Se (s-BOS) forms a conformal and crystalline β-Bi<sub>2</sub>SeO<sub>5</sub> shell. Subsequent thermal annealing introduces selenium vacancies into the core, converting it to metallic Bi<sub>2</sub>O<sub>2</sub>Se (m-BOS), which serves as a floating-gate capable of efficient charge trapping, while the crystalline BOS oxide shell provides robust tunneling insulation and suppresses leakage. This monolithic structure integrates channel (s-BOS), storage (m-BOS), and tunneling functions (BOS oxide) within a single material system. The devices exhibit a large memory window, a high charge storage density (∼5 × 10<sup>13</sup> cm<sup>-2</sup>), and a current ON/OFF ratio exceeding 10<sup>8</sup>. They also show fast programming/erasing with ±12 V, 100 ms pulses, robust endurance over 2000 cycles, and charge retention exceeding 10<sup>4</sup> seconds. Compared with other 2D NVMs employing separate materials for each functional layer, this single-material platform enables simplified fabrication and improved scalability in the 2D memory device design.