Large area, phase-controlled growth of few-layer, two-dimensional MoTe2 and lateral 1T′–2H heterostructures by chemical vapor deposition

Abstract

Molybdenum telluride (MoTe₂), as a member of the family of transition metal dichalcogenides (TMDs), gains increasing attention due to its interesting properties such as phase transition. However, it is still challenging to directly grow large area, few-layer, two-dimensional 1T′ and 2H phases of MoTe₂ simultaneously on one substrate and to construct a 1T′–2H phase heterostructure. In this work, we have developed a novel facile strategy to achieve large area, phase-controlled growth of few-layer, two-dimensional MoTe₂ and lateral 1T′–2H MoTe₂ heterostructures on one SiO₂/Si substrate directly by special substrate position arrangement during chemical vapor deposition and tuning the cooling rate after growth. We found that a slow cooling rate after film growth is essential for the production of a uniform large-area 2H-MoTe₂ film, whereas discrete regions of 2H MoTe₂ are preferred to grow under the conditions of a fast cooling rate. Furthermore, the substrate location also plays a crucial role in controlling the synthesis of 1T′ and 2H phases. The resulted few-layer MoTe₂ shows a carrier mobility comparable with that of the mechanical exfoliated ones. Our findings pave the way for the study of the physical properties and phase related devices of the MoTe₂ and MoTe₂ based 1T′–2H heterostructures.