The role of Al2O3 interlayer in the synthesis of ZnS/Al2O3/MoS2 core-shell nanowires

TL;DR

This paper presents a synthesis method for ZnS/Al2O3/MoS2 core-shell nanowires, highlighting the Al2O3 interlayer's role in maintaining surface smoothness during high-temperature sulphurization, with potential applications in protective nanostructures.

Contribution

It introduces a novel four-step synthesis strategy for heterostructured nanowires with an Al2O3 interlayer that preserves surface quality during sulphurization.

Findings

Al2O3 interlayer maintains nanowire surface smoothness

Successful synthesis of ZnS/Al2O3/MoS2 core-shell nanowires

Strategy applicable to other transition metal dichalcogenide shells

Abstract

During the synthesis of heterostructured nanomaterials, unwanted structural and morphological changes in nanostructures may occur, especially when multiple sequential growth steps are involved. In this study, we describe a synthesis strategy of heterostructured ZnS/Al2O3/MoS2 core-shell nanowires (NWs), and explore the role of the Al2O3 interlayer during synthesis. Core-shell NWs were produced via a four-step route: 1) synthesis of ZnO NWs on a silicon wafer, 2) deposition of thin Al2O3 layer by ALD, 3) magnetron deposition of MoO3 layer, and 4) annealing of the sample in the sulphur atmosphere. During sulphurization, ZnO is converted into ZnS, and MoO3 into MoS2, while the Al2O3 interlayer preserves the smooth surface of an NW required for the growth of a continuous MoS2 shell. The resulting ZnS/Al2O3/MoS2 core-shell NWs were characterized by transmission electron microscopy, X-ray diffraction and photoelectron spectroscopy, Raman spectroscopy, and optical photoluminescence spectroscopy. A reported strategy can be used for the synthesis of other core-shell NWs with a transition metal dichalcogenides (TMDs) shell to protect the NW core material that may otherwise be altered or damaged by the reactive chalcogenides at high temperatures.