Q.B. Wang, Q.Q. Xu, M.Z. Yang, Z.-S. Wu, X.-C Xia, J.-Z. Yin, Z.-H. Han

ACS Applied Materials & Interfaces, 2023, 15.

DOI: 10.1021/acsami.3c01407 [PDF]

In this study, a novel pressure-induced supercritical phase nucleation method is proposed to synthesize monolayer MoS2 films, which is promoter free and can avoid contamination of films derived from those heterogeneous promoters in most of existing techniques. The low-crystallinity and size-controlled MoO2(acac)2 particles are recrystallized on the substrate via the pressure-sensitive solvent capacity of supercritical CO2 and these particles are used as the growth sites. The size of singlecrystal MoS2 on the substrate is found to be dependent on the wetting area of the pyrolyzed precursor droplets (MoO2) on the surface, and the formation of continuous films with high coverage is mainly controlled by the coalescence of MoO2 droplets. It is enhanced by the increase of the nucleation site density, which can be adjusted by the supersaturation of the supercritical fluid solution. Our findings pave a new way for the controllable growth of MoS2 and other two-dimensional materials and provide sufficient and valuable evidence for vapour-liquid-solid growth.