Electrical and Optical Characterization of MoS2 with Sulfur Vacancy Passivation by Treatment with Alkanethiol Molecules

Abstract

We investigated the physical properties of molybdenum disulfide (MoS<inf>2</inf>) atomic crystals with a sulfur vacancy passivation after treatment with alkanethiol molecules including their electrical, Raman, and photoluminescence (PL) characteristics. MoS<inf>2</inf>, one of the transition metal dichalcogenide materials, is a promising two-dimensional semiconductor material with good physical properties. It is known that sulfur vacancies exist in MoS<inf>2</inf>, resulting in the n-type behavior of MoS<inf>2</inf>. The sulfur vacancies on the MoS<inf>2</inf> surface tend to form covalent bonds with sulfur-containing groups. In this study, we deposited alkanethiol molecules on MoS<inf>2</inf> field effect transistors (FETs) and then characterized the electrical properties of the devices before and after the alkanethiol treatment. We observed that the electrical characteristics of MoS<inf>2</inf> FETs dramatically changed after the alkanethiol treatment. We also observed that the Raman and PL spectra of MoS<inf>2</inf> films changed after the alkanethiol treatment. These effects are attributed to the thiol (-SH) end groups in alkanethiols bonding at sulfur vacancy sites, thus altering the physical properties of the MoS<inf>2</inf>. This study will help us better understand the electrical and optical properties of MoS<inf>2</inf> and suggest a way of tailoring the properties of MoS<inf>2</inf> by passivating a sulfur vacancy with thiol molecules. (Figure Presented). © 2015 American Chemical Society