Chalcogen Vacancy Engineering of Two-Dimensional Transition Metal Dichalcogenides for Electronic Applications

Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials have received significant attention for (opto)electronic applications, owing to their favorable electronic and optical properties. Various scalable approaches have been used to demonstrate the large-scale synthesis of TMDCs. These demonstrations have achieved minimal thickness variation that can be used to exploit their unique layer-dependent physical characteristics. Consequently, several synthesis techniques, including metal-organic chemical vapor deposition and solution-based exfoliation, have been explored to achieve wafer-scale synthesis of layer-controlled TMDCs. Defects (such as chalcogen vacancies) are another key factor that determines the physical properties of TMDCs. Herein, the chalcogen vacancies that mediate the degradation of the physical properties are systematically summarized. The chalcogen vacancy passivation methods are also classified into S and Se cases by clarifying the underlying mechanisms and effects. Additionally, the defect-engineered electronic and optoelectronic applications, including field-effect transistors, logic gates, multivalued transistors, photodetectors, and next-generation electronics, are discussed.