Plasmonic Au Nanoparticles Coated on ReS₂ Nanosheets for Visible-Near-Infrared Photodetectors

Even though there are various reports on the fabrication of flexible photodetectors, still there is a need for the development of high-performance photodetectors. In recent years, the plasmonic photodetection technique has emerged as one of the prominent solutions to enhance photodetection performance. In this work, a flexible and high-performance broadband (visible-near-infrared (NIR)) plasmonic photodetector is demonstrated by integrating gold (Au) nanoparticles (NPs) on two-dimensional (2D) ReS 2 nanosheets. Fabricated Au-NPs/ReS 2 showed an approximately 15-fold enhancement in the photodetection performance compared to pristine ReS 2 . Photoresponsivity of the fabricated Au-NPs/ReS 2 device in visible (Vis) and NIR regions is ∼2.1 and ∼1.3 A W –1, respectively. Significant enhancement in the photosensing performance of the device could be a combined effect of multiple factors, including localized surface plasmon resonance and effective charge transfer at the interface of Au-NPs and ReS 2 . The response speed of the fabricated device is approximately 200 ms. Furthermore, theoretical understanding of light interaction with Au-NPs is studied, and also electromagnetic simulations are performed using Lumerical Finite Difference Time Domain Multiphysics simulation to investigate the plasmon coupling effect of Au-NPs on 2D ReS 2 nanosheets. To further understand the photodetection mechanism, the energy band diagram of the Au-NPs/ReS 2 interface is drawn using ultraviolet photoelectron spectroscopy measurements.