Two-dimensional
transition metal dichalcogenides (TMDs) have a
promising future in the nanophotonics field due to their unique optoelectronic
properties such as large exciton binding energies and carrier mobility.
Among these properties, monolayer TMDs exhibit enhanced photoluminescence
(PL) by utilizing micro-/nanostructure surface plasmon polariton (SPP)
modes. In this work, we present a unique technique to achieve substantial
PL enhancement by integrating MoS2 monolayers to gold quasi-periodic
nanoterrace morphology with gradient periods on fused silica substrates.
Gold quasi-periodic nanostructures were fabricated through cost-effective
and fast ion bombardment with iron co-deposition followed by a gold
coating technique, and monolayers were deposited by a polymer-assisted
technique. Our results show clear evidence that the light emission
is enhanced due to the SPP modes produced by the quasi-periodic nanoterrace
morphology. Comprehensive spectroscopy studies were performed on monolayer
flakes with different laser polarizations, morphology periods, and
temperatures to offer detailed insights on the mechanism behind PL
enhancement. Together with numerical simulations, our results provided
a basis for understanding the PL enhancement effects and shed light
on future directions of high-efficiency light-emitting devices such
as diodes, lasers, and heterostructure solar cells based on TMD monolayers.