Enhanced van der Waals epitaxy via electron transfer enabled interfacial dative bond formation

Van der Waals (vdW) epitaxy holds the key for epitaxial growth of materials with large lattice and/or symmetry mismatches. However, despite the success in 2D materials, the goal of realizing 3D vdW epitaxy remains to be elusive. This paper takes up the challenge by studying the epitaxy of a 3D CdTe film on a vdW substrate, NbSe2, and unravels the mechanism for enhanced epitaxy. It is shown that electron transfer at the interface not only results in a Coulomb attraction but more importantly it enables an unconventional interfacial chemistry, whereby the formation of directional dative bonds significantly increases the degree of epitaxy.