Synthesis and characterisation of thin-film platinum disulfide and platinum sulfide

TL;DR

This paper presents scalable synthesis and detailed characterization of thin-film platinum disulfide and platinum sulfide, clarifying their properties and differences to support future research in 2D materials.

Contribution

It provides the first systematic comparison and characterization of PtS2 and PtS thin films, aiding differentiation and understanding of these stable platinum sulfides.

Findings

Successful synthesis of high-quality thin films of both Pt sulfides.

Distinct X-ray photoelectron and Raman spectra for each sulfide.

Guidelines for differentiating PtS2 and PtS using simple characterization methods.

Abstract

Group-10 transition metal dichalcogenides (TMDs) are rising in prominence within the highly innovative field of 2D materials. While PtS2 has been investigated for potential electronic applications, due to its high charge-carrier mobility and strong layer-dependent bandgap, it has proven to be one of the more difficult TMDs to synthesise. In contrast to most TMDs, Pt has a significantly more stable monosulfide, the non-layered PtS. The existence of two stable platinum sulfides, sometimes within the same sample, has resulted in much confusion between the materials in the literature. Neither of these Pt sulfides have been thoroughly characterised as-of-yet. Here we utilise time-efficient, scalable methods to synthesise high-quality thin films of both Pt sulfides on a variety of substrates. The competing nature of the sulfides and limited thermal stability of these materials is demonstrated. We report peak-fitted X-ray photoelectron spectra, and Raman spectra using a variety of laser wavelengths, for both materials. This systematic characterisation provides a guide to differentiate between the sulfides using relatively simple methods which is essential to enable future work on these interesting materials.