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)
ReS2 nanosheets. Fabricated Au-NPs/ReS2 showed
an approximately 15-fold enhancement in the photodetection performance
compared to pristine ReS2. Photoresponsivity of the fabricated
Au-NPs/ReS2 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 ReS2. 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 ReS2 nanosheets. To further understand
the photodetection mechanism, the energy band diagram of the Au-NPs/ReS2 interface is drawn using ultraviolet photoelectron spectroscopy
measurements.