Superconductivity is a macroscopic quantum phenomenon. Research on superconductivity has been going on for more than a hundred years. New superconducting materials have emerged in endlessly. At the same time, superconducting materials have important application value in energy, medical, communication and other fields. In recent years, with the discovery of high temperature superconductivity in monolayer FeSe-SrTiO3 system, interfacial superconductivity and superconductor-substrate interaction have become a new hotspot in superconductivity research. However, the preparation of monolayer superconductors requires extremely demanding conditions, including the ultra-high vacuum environment of 10-10 Torr, expensive molecular beam epitaxy (MBE) equipment, and specific single crystal substrates.
By adding NaCl as a promoter of Chemical vapor deposition (CVD), niobium disselenide (NbSe2) in single and small layers was successfully synthesized under atmospheric pressure. The stability of single layer and small layer NbSe2 in air is poor, and it is difficult to characterize its structure and transport properties.
Different from the strict requirements of MBE on sedimentary substrates, CVD method can be used to deposit NbSe2 on a variety of substrates (including amorphous SiO2, quartz, graphene, BN, SrTiO3, etc.), so it is expected to be used to study the effect of single-layer nbse2-substrate interaction on superconductivity. In addition, the work revealed that monolayer TMD superconductors can be prepared using a simple CVD method at atmospheric pressure. This method is expected to be extended to the preparation and research of other two-dimensional superconductors (2h-tas2, 2h-tase2, 1t-cuxtise2, etc.).
