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Surface/interface-dominated growth dynamics of novel transition metal dichalcogenide monolayers
1  Southeast University
Academic Editor: Ying Tan

Abstract:

The investigation of material growth and evolution mechanisms is of great importance for the controllable synthesis and property manipulation. In this talk, I will discuss our recent efforts in exploring the growth and evolution dynamics of novel transition metal dichalcogenide (TMD) monolayers using (scanning) transmission electron microscopy ((S)TEM) techniques, especially with the focus on the driven effect of surface/interface structures during these processes. We have demonstrated the synthesis of ultra-long MoS2 nano-channels within MoSe2 monolayers, based on intrinsic grain boundaries. A strain-driven growth mechanism is proposed that the strain fields near the grain boundaries not only lead to the preferred substitution of selenium by sulfur atoms but also drive the coherent extension and formation of MoS2 channels [1]. In addition, we have developed a co-deposition strategy to fabricate a wafer-scale network of platinum single-metal-atom-chains within monolayer MoS2 film. The stable four-coordinated motifs at the zigzag edges of MoS2 are uncovered to be responsible for the migration of platinum atoms along the growth direction, and the followed connection of inversely oriented MoS2 domains, obeying a surf-zip dynamic mechanism [2]. Besides, we also unraveled the surface-vacancy [3] guided phase evolution mechanism of PtSe2, from crystalline structure to amorphous phase. During this process, the sequential generation of selenium vacancies give rise to the decrease of coordination number, the followed displacement of platinum atoms, and the finally complete amorphization of PtSex monolayers [4].

Keywords: TMD monolayers; STEM; Growth dynamics

 
 
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