Two-dimensional (2D) materials possess exceptional properties rendering them attractive nanomaterials in next-generation electronics, optical, energy and sensor related applications. To realize the technological potential of 2D materials such as transition metal dichalcogenides (TMDCs), highly controllable and scalable routes are required. Although a variety of synthesis materials have been developed for TMDCs, it is still challenging to produce large-scale high-quality crystalline layers. Compared to the top-down methods, the bottom-up approach of synthesizing 2D materials has a wider application scope. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) routes show great promise, because they enable large area synthesis, yield excellent uniformity, unrivalled conformality and atomic-scale controllability apart from being industry compatible. For CVD and ALD of TMDCs, precursors play a pivotal role on the nature of the layers formed. In this presentation, the interplay between metalorganic precursors, deposition conditions and material properties of representative TMDCs (MoS2 and WS2) will be highlighted. Measures to circumvent the high temperatures associated with the classical CVD processes will be discussed. The studies on nucleation and growth of the layers on different substrates revealed different growth modes and nucleation density. The new precursor combinations pave the way for the direct growth of large area crystalline growth of TMDCs at moderate to low temperatures, which is a significant advantage for a wide range of applications.
Two-dimensional (2D) materials possess exceptional properties rendering them attractive nanomaterials in next-generation electronics, optical, energy and sensor related applications. To realize the technological potential of 2D materials such as transition metal dichalcogenides (TMDCs), highly controllable and scalable routes are required. Although a variety of synthesis materials have been developed for TMDCs, it is still challenging to produce large-scale high-quality crystalline layers. Compared to the top-down methods, the bottom-up approach of synthesizing 2D materials has a wider application scope. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) routes show great promise, because they enable large area synthesis, yield excellent uniformity, unrivalled conformality and atomic-scale controllability apart from being industry compatible. For CVD and ALD of TMDCs, precursors play a pivotal role on the nature of the layers formed. In this presentation, the interplay between metalorganic precursors, deposition conditions and material properties of representative TMDCs (MoS2 and WS2) will be highlighted. Measures to circumvent the high temperatures associated with the classical CVD processes will be discussed. The studies on nucleation and growth of the layers on different substrates revealed different growth modes and nucleation density. The new precursor combinations pave the way for the direct growth of large area crystalline growth of TMDCs at moderate to low temperatures, which is a significant advantage for a wide range of applications.
