Surface-Enhanced Raman Scattering Detection Based on an Interconnected Network of Vertically Oriented Semiconducting Few-Layer MoS2 Nanosheets

Abstract

As an alternative to costly metals (Au and Ag), semiconducting metal dichalcogenide nanostructures can be used as active surface-enhanced Raman spectroscopy (SERS) substrates for the detection of organic pollutants; however, they suffer from lower detection efficiency. In the present work, we analyze the semiconducting behavior of chemical-vapor-deposition-grown interconnected and vertically oriented few-layer MoS2 nanosheets by a temperature-dependent photoluminescence study. The prepared semiconducting pristine MoS2 nanosheets over Si show the ultrasensitive SERS detection of organic dyes, Rhodamine 6G, and Methyl Orange at subnanomolar (10-10 M) concentrations, which is the highest detection limit for pristine MoS2 nanostructures as SERS substrates to the best of our knowledge. The high detection limit of interconnected and vertically oriented few-layer MoS2 nanosheets as SERS substrates is attributed to the enhanced light trapping and effective adsorption of dyes due to the morphology of prepared MoS2 SERS substrates along with vibronic-coupling-enabled charge transfer between MoS2 and organic dyes. © 2020 American Chemical Society.