Room Temperature van der Waals Epitaxy of Metal Thin Films on Molybdenum Disulfide

Transmission electron microscopy, in particular selected area electron diffraction, was used to investigate the orientational relationship of Al, Ag, Cu, Mn, Mo, Ni, Pd, Ru, Re, and Zn deposited via physical vapor deposition on MoS₂ at room temperature. Past work has shown that a few face-centered cubic (FCC) metals (Ag, Au, Pb, Pd, and Pt) could be deposited epitaxially on MoS₂. However, we found that additional FCC metals (Al and Cu) could be deposited epitaxially at room temperature on MoS₂ with the orientational relationship M(111)||MoS₂(0001) and M[220]||MoS₂[1120], while a hexagonally close-packed (HCP) metal Zn was epitaxial on MoS₂ with a M(0001)||MoS₂(0001) and M[1120]||MoS₂[1120] relationship. However, the FCC metal Ni, body-centered cubic metal Mo, and HCP metals Re and Ru were not epitaxial on deposition or even after annealing at 673 K for 4 h. By comparing the results with both physical constants and modeling of the metal/MoS₂ systems, we observed that metals with a close-packed plane with six-fold symmetry, a high homologous temperature, and a low barrier to surface diffusion on MoS₂ are more likely to grow epitaxially at room temperature on MoS₂.