Electron Assisted Growth of h-BN on Gr/Ir(111)

Sammanfattning: Stacked heterostructures of two-dimensional (2D) materials are emerging as promising building blocks for a wide range of applications. These devices, which range from tunneling transistors to light-emitting diodes, use the properties of 2D materials that are not accessible by their bulk counterparts. However, with the current growth techniques, a scalable mass production of high-quality 2D heterostructures in any substrate cannot be achieved. Here we present a novel method for direct growth of 2D materials on inert substrates; Electron Assisted Growth. It is based on an electron beam generated by a hot filament placed near the surface. The electrons dissociate the precursor molecules that become highly reactive radicals and adsorb on the substrate, where they form a crystalline structure upon annealing. The method has been employed to successfully grow a boron nitride (BN) layer atop one monolayer of graphene (Gr). XPS and STM characterization have shown additional traits of the BN formation, such as the low-temperature crystallization of the BN layer atop Gr or the role of the Gr layer as a filter for atomic species that diffuse underneath. The results obtained show Electron Assisted Growth as a powerful and simple tool for growing 2D materials. Its easy implementation and scalability to other 2D materials and other substrates pave the way to direct fabrication of 2D heterostructure- based devices.