Recently,
extracting hot electrons from plasmonic nanostructures
and utilizing them to enhance the optical quantum yield of two-dimensional
transition-metal dichalcogenides (TMDs) have been topics of interest
in the field of optoelectronic device applications, such as solar
cells, light-emitting diodes, photodetectors, and so on. The coupling
of plasmonic nanostructures with nanolayers of TMDs depends on the
optical properties of the plasmonic materials, including radiation
pattern, resonance strength, and hot electron injection efficiency.
Herein, we demonstrate the augmented photodetection of a large-scale,
transfer-free bilayer MoS2 by decorating this TMD with
four different morphology-controlled plasmonic nanoparticles. This
approach allows engineering the band gap of the bilayer MoS2 due to localized strain that stems up from plasmonic nanoparticles.
In particular, the plasmonic strain blue shifts the band gap of bilayer
MoS2 with 32 times enhanced photoresponse demonstrating
immense hot electron injection. Besides, we observed the varied photoresponse
of MoS2 bilayer hybridized with different morphology-controlled
plasmonic nanostructures. Although hot electron injection was a substantial
factor for photocurrent enhancement in hybrid plasmonic semiconductor
devices, our investigations further show that other key factors such
as highly directional plasmonic modes, high-aspect-ratio plasmonic
nanostructures, and plasmonic strain-induced beneficial band structure
modifications were crucial parameters for effective coupling of plasmons
with excitons. As a result, our study sheds light on designing highly
tailorable plasmonic nanoparticle-integrated transition-metal dichalcogenide-based
optoelectronic devices.