Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore, 117456, Singapore.
Adv Mater. 2018 Feb;30(6). doi: 10.1002/adma.201704619. Epub 2018 Jan 3.
Black phosphorus (BP) exhibits thickness-dependent band gap and high electronic mobility. The chemical intercalation of BP with alkali metal has attracted attention recently due to the generation of universal superconductivity regardless of the type of alkali metals. However, both ultrathin BP, as well as alkali metal-intercalated BP, are highly unstable and corrode rapidly under ambient conditions. This study demonstrates that alkali metal hydride intercalation decouples monolayer to few layers BP from the bulk BP, allowing an optical gap of ≈1.7 eV and an electronic gap of 1.98 eV to be measured by photoluminescence and electron energy loss spectroscopy at the intercalated regions. Raman and transport measurements confirm that chemically intercalated BP exhibits enhanced stability, while maintaining a high hole mobility of up to ≈800 cm V s and on/off ratio exceeding 10 . The use of alkali metal hydrides as intercalants should be applicable to a wide range of layered 2D materials and pave the way for generating highly stable, quasi-monolayer 2D materials.
黑磷（BP）具有厚度依赖性的能带隙和高电子迁移率。由于无论碱金属的类型如何，都能产生普遍的超导性，BP 与碱金属的化学插层最近引起了人们的关注。然而，超薄 BP 和碱金属插层 BP 在环境条件下都极不稳定且迅速腐蚀。本研究表明，碱金属氢化物的插层将单层到少数层 BP 与体相 BP 分离，从而通过在插层区域的光致发光和电子能量损失光谱测量到约 1.7 eV 的光学带隙和 1.98 eV 的电子带隙。拉曼和输运测量证实，化学插层 BP 表现出增强的稳定性，同时保持高达约 800 cm V s 的高空穴迁移率和超过 10 的开/关比。碱金属氢化物作为插层剂的使用应该适用于广泛的层状二维材料，并为生成高度稳定的、准单层二维材料铺平道路。
