Proximity Effect on Growth, Crystallization and Phase Transition in 2D Materials

2D materials and their van der Waals (vdW) heterostructures weakly combined by vdW force have attracted widespread attention because of their unique properties and large degree of freedom in designing novel materials. In these material systems, we can dramatically change their properties by proximity effect. The proximity potential variation of 2D material templates has a significant impact on the growth and crystallization of the deposited material. In this talk, I will introduce how to modify the surfaces and interfaces of 2D materials and their vdW heterostructures to control their properties. We modify the surfaces of 2D materials by using plasma or highly active gas, leading to control of surface properties, such as hydrophilicity, conductivity, and band structure, which enable fabrication of low resistance contact and passivation/dielectric layer. By using encapsulation annealing with hexagonal boron nitride (hBN), we observed ordered recrystallization of metals and the reconstruction of the Moiré interface between two different transition metal dichalcogenides (TMDs) through strong interaction of matters. We also report an abnormal thickness-dependent phase transition in MoTe₂ by using encapsulation annealing. Our observations of the proximity effect on interaction at hetero-interfaces in 2D materials provide deeper insights into understanding behavior and properties of 2D materials and offers abundant choices in manipulation of 2D materials for advanced electronics.