Van der Waals Layered Transition Metal Dichalcogenide: Synthesis, and Structure-Property Correlations of MoS2 Nanoscale Material​
ABSTRACT :
Comprehensive studies revealing interesting physical properties in 2D monoatomic layers like graphene has led to the exploration of other 2D layered materials including h-BN, MXenes, borophene, silicene, phosphorene and layered oxides. Van der Waals layered transition metal dichalcogenides (TMDs) form a family of materials with versatile electronic, optical and magnetic properties. They are represented with general formula MX2 (M=Transition metal, X=S, Se, Te). These exist in various structural phases (2H, 3R, 1T and 1T'). Layered structures held together by weak van der Waals interaction can be separated into single or multi-layer sheets. Tuning the number of layers in TMDs changes its physical and chemical properties. For example, MoS2 bulk has indirect band gap of 1.2 eV, whereas monolayer MoS2 has direct band gap of 1.9 eV. MoS2 is one of the most widely explored TMD material for a wide range of applications including batteries, spintronic devices, transistors and catalysis. Bulk MoS2 is diamagnetic in nature. But room temperature ferromagnetism is shown to exist in pure MoS2 due to edge and point defects. Recently, various approaches are being employed to enhance the magnetization in MoS2. In this talk, I will present brief literature survey on electronic structure, properties and various synthesis approaches for making TMDs for MoS2. Some of the work that I have carried out on the synthesis and characterization of MoS2 nanosheets by hydrothermal process along with the future plans for the research topic will be presented.