Unveiling the Mechanisms in Surface Chemical Reactions of 2D MoS2 for Crystallographic and Chemical Engineering

Abstract

Two-dimensional materials have a layered structure, and all atoms are exposed on the surface. This makes surface chemical reactions one of the most important factors in the study of 2D materials. In particular, in the chemical engineering and crystallographic epitaxial growth of MoS2, which is a representative material of Transition metal dichalcogenides, the surface chemical reaction control plays a large role in controlling the properties of the material. This study focused on investigating the surface chemical reaction of 2H-MoS2 from two perspectives: chemical engineering and crystallographic epitaxial growth. In the chemical engineering, a study was conducted to form a covalent bond directly on the surface of 2H-MoS2 through a photochemical reaction using highly reactive diazonium salt and alkyl halide as reactants, and a reaction mechanism was proposed. In addition, in the crystallographic epitaxial growth of MoS2, a systematic investigation Demonstrated that the growth temperature has a significant effect on the crystallographic orientation of MoS2 during its crystallographic epitaxial growth. The study revealed that the surface terminal group of the sapphire substrate is strongly affected by temperature, which determines the crystallographic orientation selectivity of MoS2. These results are anticipated to be applied to various 2D materials by discovering and clarifying the chemical engineering of the surface chemical reaction of MoS2 and the fundamental mechanism of crystallographic epitaxial growth.