Large-area uniform few-layer PtS2: Synthesis, structure and physical properties

Abstract

At present, the research in field of the transition metal dichalcogenides (TMDs) was mostly concentrated in the group 6 TMDs such as MoS2 and WS2 for numerous applications like optoelectronics, sensing and so on. However, our research focuses on the group 10 of TMDs, which is relatively unexplored. Platinum disulfide (PtS2), a typical representative of the group 10 TMDs, is a newly developed two-dimensional materials with high carrier mobility, widely tunable bandgap, and ambient stability for electronic and optoelectronic applications. Here, we experimentally and theoretically investigate the synthesis, structure and physical properties of the few-layer PtS2. A inch scale of few-layer PtS2 was synthesized by direct sulfurization of Pt metal sputtered on the SiO2/Si substrate in a Plasma Enhanced Chemical Vapor Deposition (PE-CVD) furnace. And the electronic band structure of layered PtS2 was obtained by density function theory (DFT). A series of characterizations including Raman spectroscopy, Photoluminescence (PL), atomic force microscopy (AFM), scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM) and X-ray photoelectron spectroscopy (XPS) have demonstrate the quality and uniformity of the few-layer PtS2 as prepared. Moreover, the field-effect transistor (FET) was fabricated based on PtS2 in order to investigate their electronic properties, which show a p-type semiconductor behavior. Further, the work function and potential difference of the PtS2 on the SiO2/Si substrate were measured by Kelvin probe force microscopy (KPFM), showing 32 meV and 36 mV, respectively. The few-layer PtS2 samples were treated with oxygen plasma to investigate the Raman transforms, exhibiting the reduction of Raman intensity after treatment due to oxidation. The idea that this synthesis strategy can also be applied to other PtX2 devices are speculated to promote the application of TMDs in advanced optoelectronic devices.