Van der Waals (vdW) materials have emerged as a material class of significant interest for discovering new physics and for next-generation devices. To date, most research has been conducted on small exfoliated flakes or on thin films grown on inert substrates. However, in order to integrate these materials with existing semiconductor-based devices, they must be synthesized at a wafer scale on semiconductor substrates. Here, we explore the growth of Bi2Se3, a topological insulator and prototypical vdW material, on GaAs substrates. We explore surface treatments and find that an atomically-smooth GaAs surface is critical to achieving good-quality Bi2Se3 films despite the relatively weak film/substrate interaction. Calculations indicate that the interface is likely selenium-terminated and shows no evidence of covalent bonding. These results clearly demonstrate that the film/substrate interaction is important even in vdW epitaxy and provide a recipe for the growth of other vdW materials on semiconductor substrates.
Published in: "arXiv Material Science".