Samya Suvra Datta, Surojit Pande
Surface-enhanced Raman scattering (SERS) is a sensitive spectroscopic method for enhancing Raman signals on roughened metal surfaces or nanostructures. Transition metal-based chalcogenide semiconductors are effective SERS substrates due to their low cost and various tunable properties; however, their enhancement factor (EF) is rather modest. To address this issue, semiconductor heterostructures can be used as SERS substrates due to their large-scale electron–hole pair separation, high interlayer interaction, and efficient photo-induced charge transfer (PICT). In this study, a ZnO/MoS x heterostructure is synthesized and employed as a SERS substrate for the detection of methylene blue (MB). To develop a ZnO/MoS x heterostructure, ZnO is first synthesized using seed-mediated electrodeposition, followed by calcination, and then MoS x is fabricated on ZnO via electrodeposition. The heterostructure ZnO/MoS x is able to detect MB at a lower concentration of 10 –10 M with an apparent enhancement factor of 1.2 × 10 6 . The substrate is also extremely stable and robust in nature. The photoluminescence peak intensity of ZnO decreases when MoS x is decorated on it, showing less electron–hole pair recombination in the ZnO/MoS x heterostructure. Thus, the improved SERS performance of the ZnO/MoS x substrate is attributed to the efficient electron–hole pair separation at the heterostructure interface, resulting in facile PICT between the substrate and the Raman analyte.