Coincident-site lattice matching during van der Waals epitaxy.

Jos E Boschker,Timur Flissikowski,Henning Riechert,Raffaella Calarco,Lauren A Galves,Joao Marcelo J Lopes

doi:10.1038/srep18079

Jos E Boschker, Timur Flissikowski + Show 4 more

Open Access

https://doi.org/10.1038/srep18079

Copy DOI

Abstract

Van der Waals (vdW) epitaxy is an attractive method for the fabrication of vdW heterostructures. Here Sb2Te3 films grown on three different kind of graphene substrates (monolayer epitaxial graphene, quasi freestanding bilayer graphene and the SiC (6√3 × 6√3)R30° buffer layer) are used to study the vdW epitaxy between two 2-dimensionally (2D) bonded materials. It is shown that the Sb2Te3 /graphene interface is stable and that coincidence lattices are formed between the epilayers and substrate that depend on the size of the surface unit cell. This demonstrates that there is a significant, although relatively weak, interfacial interaction between the two materials. Lattice matching is thus relevant for vdW epitaxy with two 2D bonded materials and a fundamental design parameter for vdW heterostructures.

Highlights

Van der Waals epitaxy is an attractive method for the fabrication of van der Waals (vdW) heterostructures
The demonstration of improved switching characteristics of phase change memory based on chalcogenide superlattices[5] and fabrication of light emitting diodes consisting of vdW heterostructures[6], hint at the possibilities for exploiting such heterostructures inelectronic devices
If this interaction is solely due to vdW bonding or involves chemisorption, as for example observed at a hetero-organic interface[22], remains an open question

Summary

Introduction

Van der Waals (vdW) epitaxy is an attractive method for the fabrication of vdW heterostructures. Sb2Te3 films grown on three different kind of graphene substrates (monolayer epitaxial graphene, quasi freestanding bilayer graphene and the SiC (6√3 × 6√3)R30° buffer layer) are used to study the vdW epitaxy between two 2-dimensionally (2D) bonded materials. It is shown that the Sb2Te3 / graphene interface is stable and that coincidence lattices are formed between the epilayers and substrate that depend on the size of the surface unit cell This demonstrates that there is a significant, relatively weak, interfacial interaction between the two materials. It was shown that Sb2Te3, a typical 2D bonded material, can form coincidence lattices with reconstructed Si(111) surfaces[8] This was attributed to the small interaction between the layer and substrate and showed that bonding continues to play a role for the deposition of 2D bonded materials on 3D bonded substrates. The implications for the synthesis of vdW heterostructures are discussed

Methods

Results

Conclusion