Self-organized van der Waals epitaxy of layered chalcogenide structures

Highly oriented Sb2Te3 films were successfully deposited by RF-magnetron sputtering on both crystalline and amorphous substrates. A novel deposition mechanism and method are proposed based on van der Waals epitaxy. Due to the selective reactivity of the top surface atoms of the substrate with sputtered atoms, a Te monolayer is the first layer formed on the substrate, resulting in the subsequent layer-by-layer growth of the Sb2Te3 film independent of the crystallinity of the substrates. We believe that this method can be applied to the mass production of a wide range of various van der Waals solids, such as transition metal dichalcogenides and topological insulators for future electronics devices. Self-organized van-der-Waals epitaxy was proposed as a possible growth mechanism of highly-oriented layered chalcogenide materials, like Sb₂Te₃, by sputtering. It was found that depending on the composition of the substrate, there existed a selectivity of the chemical reaction between the film and substrate elements that resulted in the preferential formation of a Te monolayer and subsequent layer-by-layer growth of Sb₂Te₃. This novel mechanism enables one to fabricate highly-oriented chalcogenide films over a large area and can be applied to the mass production of a wide range of various van-der-Waals solids, such as transition metal dichalcogenides and topological insulators for future electronics devices.