Hydrophobic Si nanopillar array coated with few-layer MoS2 films for surface-enhanced Raman scattering

Abstract

In this study, we covered Si nanopillar (NP) array with few-layer MoS2 films to convert their wettability characteristics from hydrophilic to hydrophobic for applications as a surface-enhanced Raman scattering (SERS) substrate. The Si NP array was fabricated using a semiconductor process. We then sulfurized and transferred MoO3 films coated onto the Si NP array to MoS2 films. The surface morphology and cross-sectional profile of the MoS2-coated Si NP array structure was examined using scanning electron microscopy and transmission electron microscopy. The SERS results indicate that the substrate exhibits a favorable enhancement factor of 1.76 × 103 and a detection limit of approximately 10−5M for Rhodamine 6G (R6G) utilized as the test molecule, attributed to the charge transfer (CT) mechanism at the interface between MoS2 and R6G. Contact angle measurements showed that the MoS2-coated Si NP array possesses a hydrophobic surface. Our results suggest that an MoS2-coated Si NP array with CT and hydrophobicity characteristics is extremely promising SERS substrates for SERS applications.