Identifying the mechanism of single-domain single-layer MoS2 growth on Au(111)

TL;DR

This study investigates the growth mechanism of single-layer MoS2 on Au(111) using in situ microscopy, revealing how surface steps influence island formation and suggesting optimized procedures for large, single-domain MoS2 growth.

Contribution

It uncovers the role of surface step edges in MoS2 growth and proposes an optimized method for producing large, single-domain monolayer islands.

Findings

Surface steps influence MoS2 nucleation and growth.

Simultaneous growth of islands and terraces by pushing surface steps.

Optimized growth conditions yield large, step-free single-domain islands.

Abstract

The nucleation and growth of single-layer molybdenum disulfide single domain islands is investigated by in situ low-energy electron microscopy. We study the growth of micron-sized flakes and the correlated flattening process of the gold surface for three different elevated temperatures. Furthermore, the influence of surface step edges on the molybdenum disulfide growth process is revealed. We show that both island and underlying terrace grow simultaneously by pushing the surface step in the expansion process. Our findings point to an optimized growth procedure allowing for step-free single-domain single-layer islands of several micrometers in size, which is likely transferable to other transition metal dichalcogenides.