Epitaxial Growth of 2D Binary Phosphides.

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, SnP and BiP, representing typical 2D binary phosphides, are successfully synthesized on CuSn and bismuthene, respectively. Scanning tunneling microscopy imaging reveals a hexagonal pattern of SnP on CuSn, while α-BiP can be epitaxially grown on the α-bismuthene domain on CuSb. First-principles calculations reveal that the formation of SnP on CuSn 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.