Van der Waals epitaxy of continuous thin films of 2D materials using atomic layer deposition in low temperature and low vacuum conditions

Van der Waals epitaxy holds great promise in producing high-quality films of 2D materials. However, scalable van der Waals epitaxy processes operating at low temperatures and low vacuum conditions are lacking. Herein, atomic layer deposition is used for van der Waals epitaxy of continuous multilayer films of 2D materials HfS 2 , MoS 2 , SnS 2 , and ZrS 2 on muscovite mica and PbI 2 on sapphire at temperatures between 75 °C and 400 °C. For the metal sulfides on mica, the main epitaxial relation is MS 2 ‖ mica. Some domains rotated by 30° are also observed corresponding to the MS 2 ‖ mica alignment. In both cases, the presence of domains rotated by 60° (mirror twins) is also expected. For PbI 2 on sapphire, the epitaxial relation is PbI 2 ‖ Al 2 O 3 with no evidence of 30° domains. For all of the studied systems there is relatively large in-plane mosaicity and in the PbI 2 /Al 2 O 3 system some non-epitaxial domains are also observed. The study presents first steps of an approach towards a scalable and semiconductor industry compatible van der Waals epitaxy method.