Advanced Materials ( IF 21.95 ) Pub Date : 2018-01-03 , DOI: 10.1002/adma.201704619 Sherman Jun Rong Tan, Ibrahim Abdelwahab, Leiqiang Chu, Sock Mui Poh, Yanpeng Liu, Jiong Lu, Wei Chen, Kian Ping Loh
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 cm2 V−1 s−1 and on/off ratio exceeding 103. 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.
Stable quasi-monolayer BP (optical gap of ≈1.7 eV and electronic gap of 1.98 eV) with high hole mobility of ≈800 cm2 V−1s−1and on/off ratio exceeding 103 is presented. This is achieved through a two-stage LiH intercalation of multilayer BP. This strategy extends the shelf life of alkali metal intercalated materials.