Large Area Single Crystal (0001) Oriented MoS2 Thin Films

TL;DR

This paper demonstrates a CVD method to produce large-area, high-quality single crystal MoS2 thin films with high mobility and structural integrity, suitable for advanced electronic applications.

Contribution

It introduces a novel CVD growth process on sapphire substrates that yields high-quality, oriented single crystal MoS2 films with record mobility for the first time.

Findings

High mobility of MoS2 films achieved via CVD

Films are highly oriented and structurally similar to geological MoS2

Optically active with low background carrier concentration

Abstract

Layered metal dichalcogenide materials are a family of semiconductors with a wide range of energy band gaps and properties, and potential to open up new areas of physics and technology applications. However, obtaining high crystal quality thin films over a large area remains a challenge. Here we show that chemical vapor deposition (CVD) can be used to achieve large area electronic grade single crystal Molybdenum Disulfide (MoS2) thin films with the highest mobility reported in CVD grown films so far. Growth temperature and choice of substrate were found to critically impact the quality of film grown, and high temperature growth on (0001) orientated sapphire yielded highly oriented single crystal MoS2 films for the first time. Films grown under optimal conditions were found to be of high structural quality from high-resolution X-ray diffraction, transmission electron microscopy, and Raman measurements, approaching the quality of reference geological MoS2. Photoluminescence and electrical measurements confirmed the growth of optically active MoS2 with a low background carrier concentration, and high mobility. The CVD method reported here for the growth of high quality MoS2 thin films paves the way towards growth of a variety of layered 2D chalcogenide semiconductors and their heterostructures.