Effects of Acetone Vapor on the Exciton Band Photoluminescence Emission from Single- and Few-Layer WS2 on Template-Stripped Gold.

Samantha Matthews,Frank V Bright,Hao Zeng,Chuan Zhao

doi:10.3390/s19081913

Samantha Matthews, Frank V Bright + Show 2 more

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https://doi.org/10.3390/s19081913

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Abstract

Two-dimensional (2D) materials are being used widely for chemical sensing applications due to their large surface-to-volume ratio and photoluminescence (PL) emission and emission exciton band tunability. To better understand how the analyte affects the PL response for a model 2D platform, we used atomic force microscopy (AFM) and co-localized photoluminescence (PL) and Raman mapping to characterize tungsten disulfide (WS2) flakes on template-stripped gold (TSG) under acetone challenge. We determined the PL-based response from single- and few-layer WS2 arises from three excitons (neutral, A0; biexciton, AA; and the trion, A−). The A0 exciton PL emission is the most strongly quenched by acetone whereas the A− PL emission exhibits an enhancement. We find the PL behavior is also WS2 layer number dependent.

Highlights

Transition metal dichalcogenides (TMDs), such as MX2, where M = Mo or W, and X = Se, S, or Te, consist of one metal atomic layer hexagonally packed between two chalcogenide atomic layers [1,2,3,4,5,6]
Transition metal dichalcogenides have been studied for many years because the bulk materials exhibit an indirect bandgap whereas their single-layer counterparts possess a direct bandgap [1,2,3,4,5]
Phase imaging in atomic force microscopy (AFM) is a measure of the energy dissipation between the AFM probe probe tip and the sample

Summary

Introduction

The metal possesses six-fold in-plane coordination and the chalcogenide layers can be trigonal or octahedral [1,2]. In the trigonal prismatic (2H) form, the TMD will be semiconducting; and in the octahedral form (1T), the TMD is metallic [3,6]. The bond between the metal and chalcogen atom is covalent, and the layers are held together by weak van der Waals forces [4]. Transition metal dichalcogenides have been studied for many years because the bulk materials exhibit an indirect bandgap whereas their single-layer counterparts possess a direct bandgap [1,2,3,4,5]. Thin layer TMD research focused on creating new, two-dimensional (2D)

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