The preparation of black phosphorus in RP/Sn/I2 system: its nucleation agent and relatively optimal temperature program

Abstract

A convenient chemical vapor transport (CVT) approach to fabricate orthorhombic black phosphorus (BP) single crystal under vacuum is presented. In this system of red phosphorus (RP), tin (Sn), and iodine (I2), the preparation process is recorded in detail and then a relatively optimal temperature program is proposed. The preparation time can be significantly reduced, which takes only 1035 min. And we investigate that the possibility of Sn24P19.3I8 works as the nucleation agent of BP from the theoretical and experimental perspectives. And the theoretical prediction and calculation verify that Sn24P19.3I8 is similar with BP in terms of structure and the existence of Sn24P19.3I8 accorded with the laws of thermodynamics. Additionally, we observe that BP actually grows on Sn24P19.3I8 by high-resolution transmission electron microscopy (HRTEM) for the first time.