Growth of Transition Metal Dichalcogenides by Solvent Evaporation Technique

TL;DR

This paper presents a solvent evaporation technique for synthesizing high-quality transition metal dichalcogenides and related compounds, enabling detailed physical property investigations and revealing well-defined charge density wave transitions.

Contribution

The study introduces a vapor deposition method from metal-saturated chalcogen melts for producing high-quality TMD crystals, including rare-earth compounds, with detailed structural and electronic characterization.

Findings

Successful synthesis of various TMDs and rare-earth chalcogenides.

Observation of charge density wave transitions at specific temperatures.

State-of-the-art electronic and crystal structure measurements.

Abstract

Due to their physical properties and potential applications in energy conversion and storage, transition metal dichalcogenides (TMDs) have garnered substantial interest in recent years. Amongst this class of materials, TMDs based on molybdenum, tungsten, sulfur and selenium are particularly attractive due to their semiconducting properties and the availability of bottom-up synthesis techniques. Here we report a method which yields high quality crystals of transition metal diselenide and ditelluride compounds (PtTe2, PdTe2, NiTe2, TaTe2, TiTe2, RuTe2, PtSe2, PdSe2, NbSe2, TiSe2, VSe2, ReSe2) from their solid solutions, via vapor deposition from a metal-saturated chalcogen melt. Additionally, we show the synthesis of rare-earth metal poly-chalcogenides and NbS2 crystals using the aforementioned process. Most of the obtained crystals have a layered CdI2 structure. We have investigated the physical properties of selected crystals and compared them to state-of-the-art findings reported in the literature. Remarkably, the charge density wave transition in 1T-TiSe2 and 2H-NbSe2 crystals is well-defined at TCDW ~ 200 K and ~ 33 K, respectively. Angle-resolved photoelectron spectroscopy and electron diffraction are used to directly access the electronic and crystal structures of PtTe2 single crystals, and yield state-of-the-art measurements.