Microscopic Mechanism of Van der Waals Heteroepitaxy in the Formation of MoS₂/hBN Vertical Heterostructures.

ABSTRACT: Recent studies have revealed that van der Waals (vdW) heteroepitaxial growth of 2D materials on crystalline substrates, such as hexagonal boron nitride (hBN), leads to the formation of self-aligned grains, which results in defect-free stitching between the grains. However, how the weak vdW interaction causes a strong limitation on the crystal orientation of grains is still not understood yet. In this work, we have focused on investigating the microscopic mechanism of the self-alignment of MoS₂ grains in vdW epitaxial growth on hBN. Using the density functional theory and the Lennard-Jones potential, we found that the interlayer energy between MoS₂ and hBN strongly depends on the size and crystal orientation of MoS₂. We also found that, when the size of MoS₂ is several tens of nanometers, the rotational energy barrier can exceed ?1 eV, which should suppress rotation to align the crystal orientation of MoS₂ even at the growth temperature.

SUBMITTER: Okada M 

PROVIDER: S-EPMC7745401 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature