Enhanced near-infrared photodetection via exciton–plasmon coupling in Ag nanoparticle decorated MoS2/Si-nanowire hybrid

Abstract

This study focuses on developing high-performance near-infrared photodetectors using an MoS2/Si nanowire array (NWA) heterostructure decorated with plasmonic silver nanoparticles (AgNPs). Three-dimensional MoS2 stacked on vertical Si NWAs forming the heterostructure shows a broad spectral response from 400 to 1100 nm with a peak response at around 900 nm. The surface-plasmonic AgNPs significantly enhanced the detectivity of the photodetector. The AgNPs distributed on the MoS2 surface triggered plasmon–exciton coupling, resulting in higher light absorption and improved charge carrier separation. AgNPs/MoS2/Si NWAs had shown a high responsivity of 110 A/W and detectivity of 9 × 1010 Jones, which were threefold higher than that obtained heterostructure without plasmonic nanoparticles. The photodetector also shows a responsivity of 1.0 mA/W in the self-powered mode.