Epitaxial Growth of 2D Binary Phosphides

Abstract

Combinations of phosphorus with main group III, IV, and V elements are theoretically predicted to generate 2D binary phosphides with extraordinary properties and promising applications. However, experimental synthesis is significantly lacking. Here, a general approach for preparing 2D binary phosphides is reported using single crystalline surfaces containing the constituent element of target 2D materials as the substrate. To validate this, SnP₃ and BiP, representing typical 2D binary phosphides, are successfully synthesized on Cu₂ Sn and bismuthene, respectively. Scanning tunneling microscopy imaging reveals a hexagonal pattern of SnP₃ on Cu₂ Sn, while α-BiP can be epitaxially grown on the α-bismuthene domain on Cu₂ Sb. First-principles calculations reveal that the formation of SnP₃ on Cu₂ Sn is associated with strong interface bonding and significant charge transfer, while α-BiP interacts weakly with α-bismuthene so that its semiconducting property is preserved. The study demonstrates an attractive avenue for the atomic-scale growth of binary 2D materials via substrate phase engineering.

Keywords: 2D materials; density functional theory; molecular beam epitaxy; scanning tunneling microscopy; substrate engineering.