Large-Period van der Waals Epitaxy of Au on MoS2 at Room Temperature: Moiré-Engineered Interfaces for Nanoelectronics

Abstract

The continuous miniaturization of integrated circuits has driven interest in two-dimensional (2D) transition metal dichalcogenides (TMDs) as atomically thin semiconductors with exceptional electronic properties and substrate compatibility. In this study, we investigate the room temperature epitaxial growth of ultrathin gold (Au) films on monolayer molybdenum disulfide (MoS₂), focusing on the nanoscale structural evolution at the metal–TMD interface. In the initial stages of Au epitaxy, epitaxial Au grains and MoS₂ appear as moiré patterns with varying orientations. As growth progresses, these patterns converge into a dominant (12Au–11MoS₂) moiré pattern, forming a continuous epitaxial Au film with a lattice mismatch of only 0.6% with MoS₂. Analysis of the Au/MoS₂ interface reveals that large-period epitaxy induces an ∼0.6° tilt in the Au crystal planes. Density functional theory (DFT) calculations further demonstrate how local interfacial modifications contribute to lattice misalignment and strain distribution. These results provide atomic-scale insight into the strain accommodation and crystalline alignment mechanisms at 3D/2D interfaces, highlighting how low-temperature metal epitaxy on 2D semiconductors can enable structurally coherent and cleaner interfaces. This approach offers a promising pathway for engineering low-resistance metal contacts in next-generation nanoscale transistors and other 2D semiconductor-based devices.