Efficient defect healing of transition metal dichalcogenides by phthalocyanines

Abstract

We present that a thin layer of phthalocyanine (Pc) molecules can efficiently improve the optical quality of defective MoSe2 grown by CVD method. Since MoSe2 flakes are coupled with Pc molecules through van der Waals force, the structural change can be minimized, but the pristine properties can be significantly recovered. This defect healing effect can be achieved via ultrathin coverage of Pc molecules using a simple solution-mediated process. We also observed that Pc molecules with nanometer-scale lateral dimensions is useful in suppression of point defects commonly observed in mechanically exfoliated 2D TMDCs when it is improperly annealed at sub-decomposition temperatures.