Growth of Transition Metal Sulfides by Sulfuric Vapor Transport and Liquid Sulfur: Synthesis and Properties

TL;DR

This paper presents a new vapor transport method using sulfuric vapor and liquid sulfur to synthesize high-quality transition metal dichalcogenide single crystals, enabling improved material quality for nanoelectronic applications.

Contribution

The authors developed an efficient chemical vapor transport technique for large-scale synthesis of various TMDs using sulfuric vapor and liquid sulfur, enhancing crystal quality.

Findings

Successful synthesis of numerous TMD crystals in quartz ampoules.

High-quality crystals confirmed by x-ray photoemission spectroscopy.

Method improves sulfur incorporation and crystal quality over sublimation techniques.

Abstract

Transition metals dichalcogenides (TMDs) are an emergent class of low-dimensional materials with growing applications in the field of nanoelectronics. However, efficient methods for synthesizing large mono-crystals of these systems are still lacking. Here, we describe an efficient synthetic route for a large number of TMDs that were obtained in quartz ampoules by sulfuric vapor transport and liquid sulfur. Crystals of metal sulfides MgS, PdS, PtS2, ReS2, NbS2, TaS2, TaS3, MoS2, WS2, FeS2, CoS2, NiS2, Cr2S3, VS2, In2S3, Bi2S3, TiS2, ZrS3, HfS3, and pure Au were obtained in quartz ampoules by chemical vapor transport technique with sulfur vapors as the transport agent. Unlike the sublimation technique, the metal enters the gas phase in the form of molecules, hence containing greater amount of sulfur than the growing crystal. We have investigated the physical properties for a selection of these crystals and compared them to state-of-the-art findings reported in the literature. The acquired x-ray photoemission spectroscopy features demonstrate the overall high quality of single crystals grown in this work as exemplified by ReS2 and CoS2. This new approach to synthesize high-quality transition metal dichalcogenides single crystals can alleviate many material quality concerns and is suitable for emerging electronic devices.