Chemical Vapor Deposition of Two-Dimensional Heterostructures

Two dimensional (2D) materials such as transition metal dichalcogenides (TMDs) are being studied for their potential applications in opto-electronics, given their distinct structural and electro-optical properties. Laterally stacked TMD heterostructures are crucial components for constructing p-n junctions, light-emitting diodes, photovoltaic devices, and tunneling transistors. A large scale and controlled growth of these lateral heterostructures is necessary to exploit the TMDs potential for applications in flexible nanoelectronics.The objective of this research was to optimize the growth of laterally connected semiconducting MoSe₂-WSe₂ and MoS₂-WS₂ bilayer heterostructures, using the Chemical Vapor Deposition (CVD) technique.This synthesis method is relatively simple, and allows the fabrication of single and multiple junction heterostructures with the change of the carrier gas supplied during growth.Through Raman and Photoluminescence characterization, the heterostructure samples were examined to confirm chemical composition, structural homogeneity, and distinguishable interfaces of the TMDs heterojunctions. The optimal conditions for the bilayer growth of MoSe₂-WSe₂ and MoS₂-WS₂ heterostructures were established and the growth was repeated to corroborate effective replication.