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

Abstract

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[22̅0]∥MoS2[112̅0], while a hexagonally close-packed (HCP) metal Zn was epitaxial on MoS2 with a M(0001)∥MoS2(0001) and M[112̅0]∥MoS2[112̅0] 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.